Hands down, this is the best paintball game that has been released on the market. The Wii version is where it's at too.
They've gone for a realistic feel in the movement of the gun. You really need a Wii Zapper to get the most out of it, I tried with my standard gun and that didn't cut the mustard, because you don't use the (B) button at all ... you use (C) and (Z) on the nunchuck to fire.
Using the Wii Zapper is awesome. You play it like a marker, it's very sensitive as my drunk mate found out -- but you can adjust it in the settings. I've been playing through Career Mode where you can upgrade your markers, hoppers, jerseys, etc as well as adjusting your players stats. Different markers do have different fire rates, etc -- don't let the IGN review fool you into thinking otherwise.
There are a few things that the developers could still tweak to make this a much better "flowing" game, but as stated, this is the best and most realistic paintball game available. Best of all, it could be raining outside, but you're indoors happily playing away on a sunny sup air field.