Call them. That will be your best bet.
But to try to answer your questions, as far as I know, they both effect the mid/high end of the power band. The differences being just as the names imply; the mild grind will give a little less of a gain, but will run consistently with no other work. The hot grind will give you the best gain possible, but the idle will be a bit "lumpier" and you will have to raise your idle to avoid CEL's and stalling. When I get around to having mine done, I'm going for the hot. I'd rather get everything I can and take my chances with a lumpier idle. As far as price goes, I think it's like $95 per cam.