Main Street/Castle
The WDW versions are both much larger than the originals in Anaheim. This is great for visual effect, but the intimacy of Disneyland's is a plus. Main Street at Disneyland still has a unique feel to it with each shop offering a different type of merchandise for the most part (this is starting to disappear, but its sort of still there). WDW on the other hand felt like a mall to me after a while. Especially with the new enlarged Emporium.

Disneyland Forever / Wishes (Note Disneyland Forever ended in 2016 and since then they have used older shows)
Disneyland Forever debuted for the 60th Anniversary in 2015. The show takes immersion to another level with projection mapping used on the castle, Main Street Buildings, Matterhorn and Small World Facade. The show features numerous spot lights and other surprises throughout the park as well as a great fireworks show overhead while all this is going on. Also unique to Disneyland is Tinkerbell's flight path. She is able to go back and fourth, up and down as she flies through the air, compared to the original single pass on a wire which is what Walt Disney World still uses in Wishes. Wishes is more or less your standard Disney Fireworks show and it has been running since 2003 and has not kept pace with the shows at other parks. I give a very large advantage to Disneyland here.

Peter Pan and Small World
The first thing you will notice about these Fantasyland attractions is that the facades @ Disneyland are much more impressive in detail and scale. The WDW versions are very plain and dare I say boring. The interiors are very similar. Small World is the biggest difference. At Disneyland it has an exposed canal, where as at WDW it is level with the sets. The sets also seem more elaborate at Disneyland. I would give the edge to Disneyland's versions of the attractions. In late 2014 the Walt Disney World version of Peter Pan added a new interactive queue as a first act for Standby Guests. WDW offers FastPass+ for both attractions.

Pirates of the Caribbean
Disneyland's version of the attraction is much better in my opinion. The length, two waterfalls, extended caves, and reverse waterfall to exit put it over the top. The queue area and facade are better at WDW, the old fort is impressive, but the ride itself just can't compare. The WDW version feels rushed to me where as the Disneyland one takes the time to set up the story and immerse you in the experience. In Orlando the finale appears just as I am settling in.

Jungle Cruise
This was pretty much a draw. The WDW version has the "ruins" where you spend a portion of the ride inside which is interesting, but Disneyland has added some additional effects in recent years such as the explosion in the gorilla scene.. For Christmas both convert over to a Jingle Cruise for the season starting in 2013. In 2014 the Disneyland version received many more props throughout and I thought the show much better.

Haunted Mansion
The two attractions are similiar but still different. The exterior and approach to the WDW version is more impressive in my book with the mansion sitting up on a slight hill, where as at Disneyland its just sort of there. I think having the Mansion off by itself a little on the River works better than with the train and Splash Mountain so close like Disneyland. In 2011 the Mansion queue was modified and a new first scene was added outside. This is an interactive courtyard to snake through while in line and set up the attraction. I think this is great. Also the hitchiking ghosts at the end of the WDW attraction are now computer graphics and the interactions are great! The foyer at WDW with the fireplace is great to enter into (where as Disneyland its just an empty room), but the stretching rooms at Disneyland are substantially better since they do stretch (spoiler - its an elevator at Disneyland and not WDW). Having time to walk by the changing portraits before boarding the Doombuggy is nice at Disneyland. Most of the ride through portion is similiar between the two now a days, but the WDW version has a few extra scenes (the Library and endless stairways).

Tea Cups, Dumbo, Carrousel
All a draw. Pretty much the same both places. In 2012 WDW opened a second Dumbo and now features an indoor queue area which makes those hot Florida waits more barable.

Tiki Room
This is also a draw. The shows themselves are virtually identical now.

Autopia vs. The Indy Speedway
The Disneyland Autopia that re-opened in 1998 is quite a bit better than WDW's speedway.. The variety of cars and additions to the track at Disneyland put it over the top. At WDW its a very "boring" and short track. Some of the Indy theming is cool at WDW, but overall Disneyland is better due to the longer ride experience, more interesting sights along the track and variety of cars.

Disneyland RR vs. Walt Disney World RR
This is a tricky comparison. The large trains and the longer route at WDW are great, but the additional stops at Disneyland are also a plus. I enjoy both of them. I like WDWs because you get out to what feels like real wilderness. But Disneyland's acts as a much better transportation mode. Also the diaramas at Disneyland are a nice plus.

Swiss Family Treehouse vs. Tarzan's Treehouse
The WDW Swiss Family Treehouse is much more impressive to look at, but I think more kids can relate to the Tarzan version now a days. I enjoy the Swiss Family Treehouse better..

Monorail
The edge here definitely goes to WDW. The monorail is actually an essential mode of transportation. Its great to use to get around. Where as at Disneyland its still mostly an attraction. Yes you can use to to get to Downtown Disney and back, but how many people actually do that...The WDW trains are much larger, have air conditioning, and the ride is smoother. The new Mark VII trains at Disneyland are cool to look at and everyone gets a window almost but there is no A/C and there are still only two stops on the line.

Space Mountain, Splash Mountain, Big Thunder Mountain
The three Mountains are much more impressive at WDW. Having more land really makes the facades much large and more interesting. The rides themselves have mixed reactions from thrill seekers, which I am not.

Star Tours, the Adventure Continues
Exactly the same film/simulator experience. The building at the Studios is more impressive to me because of the forest set outside and there are more simulators which makes for a shorter wait at times.

Soarin' Around the World
The film and on ride experience are currently the same with the exception of the finale featuring Disneyland or Epcot depending where you are. .

Tom Sawyer Island
Another tough choice. I think WDW has the edge because it is large and has more caves to explore. But with the addition of the Pirates Cove activities to Disneylands its really a draw.

Mark Twain vs. Liberty Belle
The Mark Twain impressed me more. The ride experience is pretty much the same in terms of going around the river and seeing the sites. WDW feels more like your in the backwoods to me due to the larger area, but Disneylands journey with New Orleans Square works better.

Fantasmic
Disneyland's version is much better in my mind. The show relies much less on video and more on live action. The Peter Pan segment on the Columbia is much better than the Pocahontas segment in WDW. The finale of the Mark Twain steaming around the river is much more impressive than the Steamboat Willie boat used at the Studios. Yes almost every seat in Florida has an unobstructed view, but I really like watching NOS being transformed into a theater every night. Its still hard to believe the show is 10 years old at Disneyland (debuted May 1992).

Kali River Rapids vs. Grizzly River Run
They are both extremely well themed river adventures. I have to give the edge to GRR in terms of overall ride experience, but to Kali in terms of theming. GRR seems a bit longer and the larger lift hill and two drops add to the experience. Kali on the other hand gets you much wetter (which may or may not be a good thing). The "jungle" that Kali goes through is visually interesting and great. One other advantage GRR has is Free lockers near by to store your items in where as Kali has a center area to try and keep things dry.

Muppets, Tough to Be a Bug, Captain EO vs... themselves
These three 3D movies are the same in both parks. Some of the theater effects are slightly different but the overall experience is pretty much the same. The buildings in WDW are much more impressive from the outside, but inside are very much the same. If you have seen them in one place seeing them in the other is for the most part the same experience so you can use your time better elsewhere probably.

Toy Story Midway Mania!
The ride experience between the two coasts is identical. You play the same games in the same trams, in the same order. The main difference between the two is the queue. At DCA it is an outdoor queue and you only have a standby line (and sometimes a single ride one). At WDW the queue is inside and you have the option of using Fastpass, assuming you can get one before they are gone for the day. I was a little disappointed at WDW to see that Mr Potato Head is located in the middle of the Standby Queue so if you use Fastpass you will not see him, where as in Anaheim he is outside for everyone to see, even those walking by. The WDW queue is much more elaborate and consists of Toys, games, etc.. that are sure to bring back some great memories for many. In Anaheim you pass some of similar props as your game tram goes from the queue area back to the show building and then when it returns at the end, but it is not as impressive as WDWs. The WDW version does a much better job of setting up the story since it has the interior queu to shrink you down to the toys size. Due to the space at DCA the story is not set up as cleanly. The midway theme works better at DCA since it is on a midway, where as WDWs version being at the Studios park is kind of awkward to me.

Goofy's Sky School vs. Primeval Whirl
These two attractions are quite different, but both are "Mad Mouse" designs. I did not get on Primeval Whirl (due to lack of interest). So this comparison will only be observations. Whirl seems to be a little better because you get to spin as you go through, but Sky seems tighter and faster.

Indiana Jones Adventure vs. Dinosaur
I know its unfair to compare these two but it is the same ride technology and track layout so I thought it would be interesting.. Indy beats Dino hands down. The overall theme of the attraction is so much better. Dinosaur is an interesting ride, but most of it takes place in the dark and its just not that much fun. Compared to Indy where you see almost everything and experience several different areas. Also Indy has a much more elaborate queue to pull you into the world. The show building for Dinosaur is immersive but the storyline for Indy puts it over the top.

Test Track vs Radiator Springs Racers
We have to wait and see on this one till the new version of Test Track opens at EPCOT later this year. Based on what I have experienced and seen I would say the Radiator Springs Racers will come out on top. It is going to be hard to beat the immersion of driving through Ornament Valley, the stop in Radiator Springs and then the Race itself. Test Track is more "thrilling" due to the higher speed finale but the Racers are a much more complete attraction.

Little Mermaid, Ariel's Undersea Adventure
The ride through portion of the attraction is nearly identical at both parks. The WDW version has a much more detailed queue to handle the longer wait times. While the Disney California Adventure version features very little in terms of queue immersion having a usually short wait is a plus in my book. WDW has FastPass+ as an option too.