I received my cup in the mail today-- very pleasantly surprised by this, as I only placed the order three days ago! I last posted here, asking if I should order it from BetterLife.com for cheaper but no guarantee or from DivaCup.com for more but with a guarantee. I ended up choosing BetterLife.com, figuring, it's only 20 bucks.
I'm glad that's what I chose... because so far, it looks like the cup is perfect! I'm not due for my period yet, but I practiced a bit today, using the instructions that came with the cup. I practiced putting it in and taking it out, first. Then I decided to put it in and try wearing it for a couple hours to see if it was comfortable.
Again, pleasantly surprised-- after reading so many posts of people having problems, I was happy that it all went pretty easily for me. I found that inserting it and taking it out worked well while I sat on the toilet seat and lay back a little bit. Inserting it with the C-fold and horizontally also helped. Getting the rim through is the only part that feels a tiny bit uncomfortable, but once that's in the rest is quite easy. Taking it out was a little more difficult- it definitely wants to keep sucking up there! But just reminding myself to relax helped, then bearing down, pulling a bit on the stem got it down; and squeezing the cup with my thumb and twisting it a bit helped break the seal.
As for the actual wearing of the cup, I hardly felt it. If I thought about it I could kind of tell it was there, but otherwise I would never notice. The whole thing fits perfectly- no need to even trim the stem.
So, now I just have to wait for my next period to see how well the cup really performs. I'm sort of looking forward to it! (the last time I thought this way was probably when I was 10 or 11 years old, when I was learning about puberty and waiting for my period to come for the first time!)
I'm very impressed with the cup so far. Thank you to this whole community for all the help!