I started playing 4e at release. I ran Keep on the Shadowfell and a few adventures of my own before my group moved on. I did not touch it again for a few years until I moved and it was just about the only game in town. I played in the Crystal Caves Encounters campaign and enjoyed it. Recently I was a player in a 4e campaign at my FLGS. I know there are a lot of people out there that hate 4e, I am not one of them.
I see each version of D&D as a tool for running different kinds of games. 4e was a decent tool for running a lighter game than 3.x and was easier to introduce new players to. But it isn't the best tool I have for this kind of game. There were several games released in the 2000s that aimed for this same slot in my collection, and quite frankly Savage Worlds fills the slot better than 4e. I would go as far to say that Savage Worlds is better 4e D&D than 4e is.
The dilemma I have is that 4e is much more popular than Savage Worlds. It is far easier to find a 4e game than it is to find a Savage Worlds game. But I have no desire to run 4e ever again. I may need 4e for the purposes of playing a game at my FLGS, but if I am at the helm I am far more likely to use an earlier version of the game, or Savage Worlds if the players are looking for a minis based game.
While 4e is far faster to prep for than 3.x, it is still slower than Savage Worlds. There are enough moving parts that it is harder to create on the fly than Savage Worlds and it still winds up being more restrictive as to what the players can do. The game is very grid-centric, even more so than Savage Worlds. While I appreciate the well defined powers, they tend to limit player creativity. It is also heavily locked into the encounter format that Wizards developed during the d20 days.
I enjoyed the whole "Points of Light" idea, and I was really excited about it when I got the Worlds and Monsters preview book. But I feel like they never really developed it fully. While there were a bunch of changes to the Forgotten Realms that got the internet worked up, they did not create a new setting with 4e in mind that leveraged the idea.
This means that I will be keeping a few 4e books, mostly the essentials stuff I will need as a player, but getting rid of the rest. Sorry 4e, I really did have a good time with you, but it is time to go.