Well I have to say, this has got to be the hardest anime to review and rate that I have come across so far. It is one hell of a mixture. But I did had a great time watching it, was very entertaining and that is what really matters.
On the plus side, I loved the setting/premise, a world where virtual reality has been perfected and MMORPG's truly come to life. The RPG gamer in me was really happy while watching this anime. DAMN I wanted to be in SAO so bad.
The animation was great, especially that of the action sequences. I loved em. Coupled with amazing soundtrack, they really became epic. Protagonist was very likable and cool. The heroin was hot.
Now on the bad side, the anime felt really rushed in the beginning. It actually felt like I skipped an episode couple of times. Would have been better if they stretched out the first arc into 24 episodes or so, would have been much better. It got a little too much lovey dovey too later on, which was off putting. T
he side characters were good BUT they got very less screentime, way too less. It was like the anime forgot about them. And then there was the second arc. It didn't suck as bad as many said it would but still it was nowhere near as good as the first arc. IT just didn't had the same feeling as the first arc. The setting in it was cool, had a lot of Final fantasy vibe to it. But the love stuff was lame and pointless.
As for the rating, well I would give it like:
First arc (1-14 episodes) 8.8/10.
Second arc 6.5/10.
Overall, despite its flaws, I somehow still found it to be very enjoyable and was engaged in it a lot.