ummm...you realize that night trains are 123mm underfoot right? Invaders are 83mm underfoot - that's a huge difference.
Night trains are more of a powder/crud jib ski, whereas the invader are pretty much a strictly park ski - don't get me wrong, the night trains will go into the park just fine, it just isn't their designed purpose. I'd say if you're looking for a ski that's solely for the park then go with the invaders, but if you like to play around in the powder or play around on groomers and stuff more than in the park than go with the night trains.
~WAKIN' UP THE NEIGHBORHOOD TONIGHT!~