I've used the Emigi before. I went for them because I generally prefer things on the small side. I couldn't really feel it once it was inside, so if you're looking for something to stimulate you as you walk around you might want to look elsewhere (though some folks do feel it). I found the Luna Beads to be much more pleasurable, and they now come in a mini form that I'm eager to try.

Since I'm not actively trying to tone my PC muscles I never paid much attention to how well any of these exercisers worked in that regard. It's been a while since I've used them, though, so I'll have to keep better track when I start up again.

Good advice everyone