Fully keeping in mind that mine is a biased opinion, yeah, I like it. I feel like I'm playing D&D, and at the end of a session I don't feel like we've done anything that we wouldn't have done in a 3E game. I'm liking my wizard, and enjoying playing an eladrin (though it's taken me a few sessions to get a good mindset down for him). There have been a few speed bumps, but each revision of the game seems to be fixing more and more of those. Am I confident in it? Well, yeah. It's hard not to be. But then again it seems like the kind of game I would like: lots of options, quick gameplay, and I never feel like the "second banana" in combat (whereas my paladin of Heironeous in the last game was largely relegated to a support role). It's also a very cooperative game, which is right up my alley; as I mentioned, finding the nice little interplay between my wizard and the warlord was one of those epiphany moments in last night's game that made me enjoy the session a lot.
I dunno, maybe it's just me (and I'll fully accept that as fact if it's true) but I really feel like the experience I'm having at the table is what I've come to expect from D&D over the last 8 years.
Putting on my game designer hat for a second, though, I think 4E is going to be SO much easier to design and develop material for. Having already done so a bit, and having seen how the mechanics are put together, it kind of amazes me that it wasn't done this way sooner. I know this is going to frustrate people a lot with its vagueness, but having all the math essentially done for us ahead of time seems to be letting us focus more on the creative side of things than on the balance side of things.