If your a fan, you'll enjoy it.
The graphics are great, although I'd enhance the lighting if I could. There are parts of the game where items or structures will be on fire but they do no illuminate the area... this looks very cheesy back to Doom/Duke Nukem days. For instance the flame thrower would not illuminate a room when used, flaming aliens would not either. The flash light is pretty dim, but you get unlimited flares which wouldn't stay out very long.
The AI for marines is terrible. There are not many times you'll have a partner, but when you do, they rarely attack aliens that get by them.
The gameplay is a lot of fun. I thought I wouldn't like the melee blocking/countering aspect but it enhances the game for me.
I'm loving the multi-player portion. Just with you could hop into games already underway. Matchmaking is slow and tedious.
All in all, if you're a fan of the serious you'll enjoy this game. If your not, then you'll probably not like the game or the multi-player. The MP portion is a little new for console gamers, but it is very fun once you get the hang of it.