Disneyland Railroad/Walt Disney World Railroad: Better at Disneyland because of the Grand Canyon/Primeval World dioramas. WDW's scenery is sparse and bland, with nothing of interest. At Disneyland, just do Tomorrowland to Main Street to see the dioramas if that's all that interests you.
Astro Orbiter: Higher up at Walt Disney World, and with better views.
Buzz Lightyear Astro Blasters/Space Ranger Spin: Guns have more mobility at Disneyland, scenery is basically the same. Disneyland's is more skill based, there aren't as many insanely high point targets.
Space Mountain: Right now, Disneyland has Hyperspace Mountain which has a lot of screens that allow you to see more than WDW's version. I still prefer Disneyland's because of the soundtrack and smoother ride experience.
Snow White's Scary Adventures: Still exists at Disneyland, and is shorter. The story is less coherent, but I still like it more than what Walt Disney World had. Very similar to the Paris version.
Dumbo: Longer waits but better views at Disneyland, since WDW's has been moved to Storybook Circus.
Mr. Toad's Wild Ride: Never rode it in person at WDW, but the extinct WDW version seemed to have better scenery.
Peter Pan's Flight: WDW's version is sad. The tin-foil LED volcanoes pale in comparison to anything in the Disneyland version except the new London scene.
It's a Small World: WDW's is much shorter and has a pitiful indoor exterior with lots of patchy glitter. At least show them the exterior if they don't want to ride.
Big Thunder Mountain Railroad: The new effects at Disneyland's version make it better than WDW's by a landslide.
Jungle Cruise: Disneyland's holiday overlay is better than WDW's, but WDW has the temple sequence while WDW doesn't. I've also had better experiences with skippers at Disneyland than WDW, but that's not guaranteed.
Tiki Room: Neither version has Offenbach anymore, but Disneyland's show is longer, has a better preshow, lets you eat a Dole Whip in the theater, and doesn't have the awkward edits that WDW's has.
Pirates of the Caribbean: Twice as long at Disneyland, and with shorter waits.
Haunted Mansion: Exterior and queue are superior at Disneyland, but the few extra scenes in the WDW version push it over the top. They should ride it anyway to see the Hatbox Ghost.
Splash Mountain: The score at Disneyland is better (more big band, less country), but the storytelling is better at WDW.
Winnie the Pooh: Much shorter waits at Disneyland, but better effects and storytelling at WDW.
Soarin': Assuming the ride will be the same on both coasts when the new film premiers.
Tower of Terror: WDW's is better. Queue is better and ride is better.
Star Tours: Same on both coasts, but different queues I think.
Toy Story Mania: Same on both coats, but shorter lines and worse outdoor queue at Disneyland.
Little Mermaid: Same at both parks. Better queue at WDW, shorter line at Disneyland.