I went for the first time in my adult life (I think I went once when I was a kid, almost 25 years ago) near the end of August last year, about five months before a WDW trip.
It was nice - but I think I prefer MK (and I'll admit I grew up with trips there every few years.) The big problem was what some people like best - the space. It's just so darn cramped! It's livable during the day, but when the fireworks or Fantasmic are going, it was nightmarish! We weren't able to watch the fireworks (which I regret, after seeing video of them since then) because there were ropes up everywhere and cast members with flashlights hurrying you along and telling you to move if you stop. You're basically stuck in a narrow one-way corridor during the fireworks. During Fantasmic is slightly better, but still nuts - it's amazing that they're able to put the show on with no real bleachers, like at MGM.
Next time, I guess we'll have to camp out early to get a seat to watch Fantastic or the fireworks.
As for the attractions - the new Space Mountain is terrific, no question (but the WdW one is still lots of fun.) Indy was quite good though I'm not sure that it's that much better than Dinosaur. The queue at Indy was good, though - many of the DL rides have very basic queues compared to the MK ones, and you're more likely to be out in the sun.
HM was about equal except for the new floating Leota, but presumably MK will get that. Pirates was slighly better but not significantly so. I didn't get a chance to try Splash as the line was just too long. And why doesn't Matterhorn have Fastpass?
It is nice to see the original Tiki Room, instead of the debacle at WDW, and the Jungle Cruise has the fun piranha - but no tunnel. And DL does have Mr Toad's.
I did enjoy our meal at Blue Bayou, and can't comment on the hotels as we stayed off-propery. (Next time I'll probably use points for the DL Hotel.)
On the other hand, DL doesn't have PhilharMagic, Stitch's Great Escape (OK, I prefer Alien Encounter but this was not too bad), and the dining at MK is much more extensive, at least from what I saw. Outside of Blue Bayou, what else is there that is a gotta-do, dining-wise?
Then there's CA Adventure... Screamin' was closed when we were there (after the death), and overall there really wasn't much too it. I hated the Pier area (that's exactly what I do to Disney parks to AVOID), Tower of Terror can't compete with the WDW one (especially the theming outside), and Grizzly River Run is fine but it's just a regular raft ride that you can get anywhere. Soarin' didn't do much for me and has a better queue than the WDW version but otherwise it's identical.
If you've been to WDW, the only reason to see CA Adventure is the Electrical Parade and maybe Screamin' IMHO. I can also confirm that yes, the locals don't like CA Adventure at all, at least my friends who live there. The park was nearly abandoned despite the crowds at DL when we were there.
Ultimately - Walt really learned from the problems of DL with MK - the extra space means not just more room for people, but most attractions get more of their own space, the castle is much more impressive (but that's just one person's opinion), there are more dining options, there are more hotels... and that's not even counting Epcot, MGM, AK, etc.
Both DL and MK are excellent parks and well worth a visit, but the cramped quarters of DL really were a bummer and unfortunately, that's one of the main memories I took away, of the fireworks crush. Next time I'm in LA though, I'll definitely be back.
DL and now I want to return. 
