The Diva seems to work best, but occasionally I have issues getting it to pop open. I can get it all the way in and mostly unfolded, but it almost feels like there is a dent or soft spot in the side. I can spin it all the way around and it feels like the rim is all the way open, but the dent is unnerving and I don't trust it. This doesn't happen all the time, but when it does the only way I've been able to fix it is by taking it out and starting over, which is annoying because I don't like to re-insert without rinsing first. I added a couple of holes last month, but it didn't seem to make much of a difference.
I have the opposite issues with the Lunette. I can get it in and open with no problems, but it leaks EVERY time. I have ruled out a dangly cervix simply due to the fact that I can fill up the Diva with no issues. I usually end up switching back to the Diva after a few hours because I can't take the leaking. This cup is also a little uncomfortable to remove because of the stiffness, but I think it's a fair trade because it is so much easier to open.
I prefer the style of the Lunette, but the Diva seems to be a better fit for me, so I'm wondering if there is a 3rd cup out there that meets all my needs. I would prefer a colored cup with a solid or non existent stem, and I'm thinking something firmer than the Diva might solve my problems with insertion. Removal is not an issue with either, even without the stems, so I think I could probably go a little shorter, but not too much.