My two cents worth: We just got back from DL on Monday morning and had a lot of converstaions about which is better while we were there. Been to MK more than 20 times and been to DL 3 times since '98.
Pirates is MUCH better at DL. So is Space. Splash is rushed but just different. If it wasn't rushed, I'd call it a draw. Tarzan and Swiss are just different. Both have good and bad points, largely dependent on your age. I grew up with Swiss, so it will always have a place in my heart. Lots of folks haven't seen the movie and don't get it. Tarzan is more fun, for sure. Swiss is more nostalgic. Slight edge to Tiki's in DL as it is a lot closer to the original since they've shortened it a little at MK. Tomorrowland is better at MK, without a doubt but I think that may change with the Iron Man addition. Any "land' that has Carousel of Progress has an advantage as it is just so "Walt". The Mansion holiday was awesome, but I prefer the original "look" as an ongoing thing and prefer the exterior of the one in MK and the "show" while waiting. Dark ride advatage in a big way to DL except for Pooh, which is better in MK.
The biggest difference for me is the overall look of the park and it's feel. Can't quantify this, but DL is much prettier, more intimate and just more "Disney" than MK.
I can't speak to the parking issue as I didn't drive there, but after renting a car and driving to Burbank for a Disney Studio tour, all SoCal residents have my sympathy. What a mess traffic is there.
Finally, MK has the "castle" shows which blow away DL's fireworks. Fantasmic is much better at DL than what there is at The Studios in Florida. The setting can't be beat and having the Mark Twain and the Columbia in the show is mind-blowing.
Personally, I prefer DL to MK. If you asked if I preferred Disneyland Resort to Walt Disney World, well, don't ask, I couldn't decide. WDW for size and scope, Disneyland Resort for ambience and "do-ability". Depends on what you want.