Not bad, but not great.
It could use more Wiimote actions beside parachuting and grenade tossing. The parachuting is a blast. You hold the controlers like you would the lines of the chute and pull and twist to land. I only wish there was more of it. Tossing `nades is fun too. You hold in the B button and make a throwing motion, letting go of the button to let go of the pineapple. Very satisfying. On the flipside, most of the motion controls on the nunchuck (jump, crouch, reload, 180 turn) are frustrating at best, and fatal at worst. I gave up on them about 5 minutes into the game. However, they are all mapped to buttons so it is not a big problem.
The only other problem I have is the hit detection. I've had many-a-Nazi dead in my sights only to miss. And sometimes your target dies a second after you fire. I don't know if this is due to poor detection, or perhaps my squad mates got them.
No, this is not the best FPS on the market. But it is better than you'd expect from most of the "professional" reviewers. If you are into WWII shooters, then definately pick it up. If you are looking for a decent shooter for the Wii, then pick it up. All others, rent it first.