I too would be a little bent at receiving damaged goods. I am not defending Nitro, but they do not make the plane and they are not the ones handling it in route to you. The plane was packaged, shipped to them from China, then they send it out to you. I would think that it was tossed around pretty good before it ever hit American soil.
As said above, post on RCD in the nitro plane support forum. They monitor that one more so then they do this forum.
http://www.rcdiscuss.com/index.php/board,84.0.html
"How much damage is aceptable to you? " For me, it is not the amount of damage, but how easy the repair is. I have had stuff from Tower, Horizon, and most of the other places I order from show up with damage now and again. If it is "EASY" to fix, I find it less trouble to fix then to send it back and wait for it to show up again. But that is just me.
If you fly the plane a lot, you may end up putting adding hinges to replace the live hinge. I have (2) foam planes I have had to hinge because the live hinge starts to tear.
Buzz.