I don't think it really matters to most guys. Virgins can either be good or bad experience depending on the woman. It's sort of a turn on, but it could be a downer if things don't go as planned.
Because it is exciting and different. If the woman enjoys it, it can be pleasurable to both, but sometimes it can be painful to the woman which should make it a turn-off for a real partner. Most guys just want to try it because it is considered .