I prefer studs since you aren't removing them from the case each time you pull the head, though I admit that's probably moot since they will likely never get removed again by me. That said, my singles have bolts because that's what they came with and I didn't care enough either way to change them.
I also only use stainless for the bolts that hold on sidecovers and things like that. Nothing structural. And don't forget the anti-sieze on any stainless fasteners.