Ah, I love my "instead" cups. A little hard to get used to, so make sure you wear pads at first. I have found them a little, um, big on occasion, but once you get the right angle figured out, it's great. I feel them less than tampons, and there's none of that awful half-absorbed-is-this-thing-made-of-sandpaper feeling. I read about the reusable sponges, but the infection control nurse in me thinks that unless you're going to boil the things between uses, they could breed toxic shock syndrome or pelvic inflammatory diseases or at least yeast infections.
I was just reading H's American Family Practice journal last night, and in it was a statement from the editors about the safety of continuous birth control or "quarterly" periods. They made the point that women these days hit menarche earlier, have fewer kids, breastfeed for shorter periods and live longer than ever, and so are having more periods than ever. This supports the theory that there's no biological benefit for bleeding monthly. They also cited a well-done study on the efficacy of continuous hormonal birth control, that found it just as effective as the traditional kind.
Anyway, here's a vote for the keeper/instead cups.