Clover clamps can be a lot to take, especially for someone new, or someone who has a lot threshold of pain <> pleasure tolerance. I have found that using the tweezer-style clamps, or another adjustable one really are better to start out with nipple play. Also, because clover clamps tighten as you pull away from the nipple, they are best used in some sort of play where the wearer has to choose from the worst of two sensations. It certainly works well with the mindfuck scenario!
The device is interesting, but probably not one I would play with personally. I actually like to be the one tormenting (though I'm sure a victim or three would say it wasn't all bad...
my "victim". The nipples are fun to play with, and can be quite responsive. I think I'd much rather have my "victim" impaled on a nice vibrating dildo with clitoral stimulation and while my partner in crime vibrates away I could turn my attention to the upper part of the body.
Twofers anyone?