I own one and they are quite good for what they're designed to do, its better than your hand that's for sure!
It isn't as good as a real woman though but it's good for when you can't have one
Yeah I've got one...not as good as the real thing, but when you're looking at a change of pace from your hand it varies it up some. It can be a little noisy to use - the cap on the end often jiggles or leaks air pressure as you move in and out. So if you have roommates it might be a bit of an issue if you're trying to stay quiet.