I stopped playing the game about a month ago. It wasn't even a conscious decision, I just started logging in less and for not as long, and then just kind of stopped logging in altogether.
I haven't "quit" - I just stopped playing.
I check the webpage periodically to see if there's been any updates or changes, and until those changes come I probably won't be playing very much PoE. Most of my issues with the game have already been addressed in this thread (melee, desync, maps, etc.) so I won't go into them again.