I think they are nicely done. There are marks on the sides where the aluminum is rolled. I'm assuming they can be sanded down and polished completely.
I mounted one of them, but my brackets weren't stiff enough. I'm going to take it off and come up with better brackets. At the moment work is going crazy, and the car is in the shop for a head/cam package.
I had clamshells, and I got rocks in the seat and my hair all the time.
For the last couple of months I ran with no fenders, and there was really not much difference (bad either way).
I think fenders mostly make a difference in shieling water if the road is wet.