i thought the diva cup was a bad idea for my body, till i checked out the mia cup directions and discovered that most of my problems with occasional leaking, insertion trouble, "spinning" confusion stemmed from the really unclear directions that diva cup gave, and that when i tried to solve my problems, i was asking the wrong questions, simply because i had a certain method stuck in my head, and thought i knew what i was doing, and there must be something wrong with the cup or with my body.
just one example: the "U" shape or the "C fold" confused me. they said to point the "bottom of the U" towards "me" but errr, it's going into "me" so anyway it points is toward "me" ... apparently i was doing it upside down, thank you MIA!!
i would get a different cup if i had to do it again, but mostly because of diva's directions (and non-anatomically-helpful diagrams).
Lastly, diva used to say you could keep the cup for "up to 10 years" but their website now says it should be changed every year, or oftener if you accidentally drop it in the toilet or other unsanitary conditions. err, boiling anyone? environmentally unsound?