I was, initially, pretty optimistic about 4e when it was announced - I had liked SWSE and the scuttlebutt was that 4e was based on that design direction - but this was kind of the opposite of my feelings for 3e when it was first announced. When 3e news started coming out, particularly on Eric Noah's site, the game's changes won me over. Again, the opposite happened with 4e and I became less and less confident it was going to be a D&D edition I liked.
When the books came out, I got myself the PH and we started playing it regularly. I bought the DMG. And then I stopped getting the books. The game just wasn't resonating for me. The fights were grindy, I didn't like the power structure, I didn't like the scope of the spells being so reduced (and though rituals were a nice idea, they really weren't a panacea), I didn't like the focus of the game around "the encounter" and virtually little else, and I didn't like the magic items.
We continued to play for over a year and then even the 2 players in the group decided it was too much of a hassle. Now, it gathers dust on all of our shelves and we're play testing D&D Next and otherwise stick with 3.5, SWSE, or Torg.
Of my other gaming group, the one regularly playing PF, I'm the only one who has tried 4e in any extended way. Two others have tried it a couple of times and one worked in game distribution and knew a lot about it. None of them like it.
Of the other groups I know of who shifted to 4e, one DM is pretty sick of the stun locking powers and finds running high levels to be not that much fun. I hear they're looking into PF now. And the other group has largely shifted over because of Paizo's cool APs and because the teenage boys seem to prefer PF/3.5.