I bought it last night for $35 after gift card. I am definitely not disappointed.
Let me say first that I tried the NCAA 08 demo a few nights ago and I was totally unimpressed. The gameplay was okay, as were the "action" animations, but the graphical polish was lacking outside of the player models. Also, simple animations such as linemen getting down in their stance were ugly and robotic. The sideline people were N64 quality. Though I just mentioned the bad parts, it was an okay football game overall, but with a few things that really irked me about the presentation.
2k8 is what I expected out of an early next-gen football title. It definitely feels next-gen to me; it impresses with the animations and graphical polish (though the player heads could use a little work). I was worried about the player-chatter and cutscenes, but they impressed me as well.
It plays a lot like 2k5, but with improvements in every aspect of the gameplay and presentation. I couldn't recommend it at $60 for people who will really miss a deep single-player mode. I would recommend it for anyone who enjoyed 2k5 because of the gameplay. Online is very good with almost no noticeable lag (except kicking). The AI has improved, as has the commentary.
Though some of the standard features such as franchise mode are absent, the actual gameplay is the best I've experienced in a football game.