We saw this yesterday - MAN was it awesome! I have no idea why it is getting bad reviews, it just so incredibly awesome. Plenty of special effects, action etc and great romance story on the side.
I almost started crying at one point and Hubby hissed at me "You aren't going to cry at a WILL SMITH ACTION MOVIE are you?". But it was great - it was funny and exciting and FRESH! A new idea AND it has a plot twist that you won't see coming.
I give it MANY THUMBS UP - GO SEE IT!