Powder coat, and I wish mine were plain aluminum.
In the deep, it's great as the snow does not stick to it very well, however on the trail, and getting into and out of the deep, as stated snow does not stick to it when you might actually want it to for cooling. I ride with a number of other doos, and when they are on the trail, and have some snow and ice built up on the top of the tunnel, (and are still running cool) I am hot, and have the scratchers down with not a flake of snow sticking to it.
Just my opinion, and I'm sure we will see others about it, but I would and will prefer plain ol aluminum on the 2013 snocheck. That, or it will hit the sand blaster shop down the street and remove it from the back of the tunnel.
If you ride in powder all the time it's great, if like most of us, and still have to get in and out of the deep, well, I've stated my opinion.
Again, just my opinion.
Yella'