I have some cheap ones. I do a few KB exercises, more as an experiment at this point. Mainly the "around the waist pass" and H2H (sort of "juggling" the bell back and forth) using light KB's. I also do some light squats holding a KB, windmills (exercise for the obliques,) and some farmer's walks with two KBs. Nothing major. I like circuit training so I'll throw in a couple KB exercises for variety while I'm doing overhead presses, pushups, squats, lunges, etc.
I don't do the basic ballistic exercises. I aggravated my lower back a while ago and I'm not going to take a chance by doing swings (because of the bent over position,) and I'm not very comfortable with the "downward movement" on the snatch (after you've exploded the KB over your head, arm straight, and you bring it back down between your legs before exploding again.) It's quite a "ballistic shock" on the shoulder, in my layman's opinion. Both the lower back and shoulder are very vulnerable areas, so I'm going to tread lightly when it comes to exercises like those.
The ballistic exercises I think are more for people who are already in great shape. I'm by no means in great shape, so I don't think I'm advanced enough for a lot of what those guys are doing. A lot of the people who use KB's seem to be athletes, like MMA, powerlifters, etc. They're probably used to putting their bodies through some stress and strain. They have a very active forum at dragondoor.com. They know a lot more about it than I do, that's for sure.