I've used a divacup for a year or so and it's great. I don't know if my cervix is low or high. It's just short of the middle knuckle in, so about 1.5" in. I love the length of the diva as it leaves enough room to pinch the base to release the suction without touching the cervix, which sort of sits in the cup Also, even though I have the stem trimmed, the base sits right at the entry of my vagina so I don't have to "fish" for it and I don't feel it. I have the mirena now and I'm afraid to use the cup. I need a new cup anyway as my diva is a little dingy and the suction is hard to release (plus I want pretty colors!). I want something with enough length to avoid accidentally grabbing the string (it's been cut short, about 1cm). I'm between a large Ladycup or a large Lunette from looking at this chart:
http://menstrual-cups.livejournal.com/1285963.html
I'm leaning towards the large Lunette as I feel the stiffness will aid in releasing the suction and their site explicitly says it's ok to use with an IUD. What do you think?