My preference has always been for co-op, so even if later versions get some different extra features, the 4 player co-op and the fun times I've had with the game are more than enough.
Likewise, think of it this way. If it's not exclusive, we're looking at 4-6 months before it comes out for any other system. In that time, we'll probably have Resistance 2, Metal Gear Solid 4, and I forget what else released.
Hazy, while I think it looks good, really is just a hold over FPS until R2 comes out with 8 player co-op.