I have divided views on SAO. On the one hand, I don't think it's very good. On the other hand, I keep watching it anyways. There's at least two aspects to this.

The frustrating thing about SAO is that a great many of the small-scale details are nice, it's just that the large scale plot and characters are stupid, cliched in a bad way, and irritation-inducing. I like to fool myself that this is the sign of a good director being forced to closely follow not-great source material (presumably in order to appease the fans of the original light novels so that they buy the ever-important Blu-ray releases). These little things combined with the good production values are a large reason that I keep watching despite all the stupidity.

Another reason that the show is more interesting to me than you might expect is that SAO is very much about a game and it never loses sight of this. At the start of the show I expected that the 'trapped in a game' part of the premise would mostly be used to justify ye generic fantasy setting and you could just as well have transported all of the characters to some alternate dimension. This turns out to be not at all the case; that the characters are playing a game is a constant presence in the show and makes it far more interesting than yet another fantasy setting. I may grouse about the characters being stupid in how they approach SAO the game, but they're realistically stupid in that many of their behaviors feel like recognizable MMO gamer behaviors. I've seen plenty of fantasy shows, even plenty of shows about people from this world pulled into a fantasy world in various ways, but a show about a fantasy game is relatively novel.

(One of the frustrating things is that SAO shows flashes of having something interesting to say about the whole 'stuck in a game' premise but then generally drops or fumbles it immediately.)

Finally, it's clear by now that Sword Art Online is not a good adaptation. There are many nonsensical moments and when they happen it frequently turns out that the show has left out important information, dropped relevant scenes entirely, or made changes to a scene so it makes less sense (for example, see the comments on this summary of episode 19). At this point SAO is less a standalone adaptation and more of a highlights reel for fans of the original work, who have the context to fill in all of the missing pieces and make the characters less stupid. If you lack the context, the show remains comprehensible and watchable but it's periodically stupid and jarringly odd. This is clearly the fault of the studio and the core creative team for the anime.

(I'm sure that the SAO Blu-rays will sell like hotcakes anyways.)

Sidebar: on .hack

Speaking of shows about (fantasy) games: I know about the .hack franchise. I think I watched part of the first episode of .hack//Sign and stopped, and saw one episode of .hack//Roots and was very much not impressed (I actually just found my old capsule review of it, which is part of a personal historical artifact that I may revive someday). Maybe sometime I will take another run at the franchise but commentary about .hack//Sign being slow does not make me enthused.