I saw it as well, I really liked it. I haven't read to original book so I don't have anything to compare it to though. I thought the breakdown in human behaviour of the infected humans was interesting.

[spoilers]
Although the ending was good, it could have been so much better if Will Smith ran into the infected humans shouting "I am Legend", that would make a memorable moment. I thought the quality of the film was good but it lacked in memorable scenes.
[/spoilers]

I've made the spoiler bits white, you'll need to highlight them to make it visible.