I used one for years, especially when I was traveling and living in countries where it's hard to find tampons.
Can be a bit messy when removing, takes some getting used to, and does sometimes leak at night, but overall, great. However, the rubber or whatever material it's made from definitely seems to have worn down. I would have to buy a new one now, after about 5 years of having had it. I got mine through the mail and it might have been the diva cup someone mentioned.