As mentioned before, I personally liked Sword Art Online. But then I've found that my tolerance level is pretty high, for anime/TV/movies that others deem bad. I get too engrossed in the storylines and characters to be able to take a step back and realise that a show may be cliche or bad or whatever. That tends to lead me to enjoy shows that others may dismiss. I find that I'll often enjoy an episode or movie, go online to see what critics think, and find it was panned.
That being said, as far as shows about MMOs go, I like Log Horizon more than SAO. It focuses more on the game world and what's going on inside it, feeling, at times, more like a depiction of an MMORPG. I have yet to check out .Hack. I just remember waiting impatiently for the games to be localised (something which I thought would never happen, back then; though, I never got around to playing them either, when the finally were!).