In a few words.... Beautiful, but boring.
I know this is supposed to be a totally different genre than the GTA series, but it is hard not to draw some comparisons. For me, I have found the most rewarding part of the GTA series is not the missions (although they provide a fun distraction now an then), but the free-roaming and (almost) fully interactive environment. Let's admit it - it's fun to cause to mayhem! I love just driving around the huge landscape and exploring. So do my kids (I've modded my version and removed almost all the bad stuff).
If Atari/Eden Studios would make the environments as interactive as the GTA series, they would have a serious hit. The missions are pretty interesting and the graphics gorgeous - it's just missing that "fun" factor.