I've been looking at those rotary headshavers, and wanted to try one. My old triple head is getting really old. The reviews for the rotaryS aren't really good.
My advice is: Don't spend a ton of money on one because the more expensive ones won't necessarily give you a better shave. I can't speak to the longevity of the cheaper shavers but I feel it's better to buy a cheap one that works good for a month than to spend a lot of money for something you want to throw in the trash can after one use. The shaver I got comes under several names so no matter what place you get it from, it's still the same shaver. Weird, I know.