Fair warning: there is Aunt Flo discussion ahead. It's not too over the top but possibly TMI. If you're one of those guys who freaks out at the mere mention of the word "tampon", you probably won't want to continue reading (heck, you probably stopped reading the post already, so that isn't much of a problem =P).
My Keeper came in the mail today, and since I'm on the tail end of that time of the month, I figured I might as well try it out. While Googling for information on this and the Diva Cup (a similar product made out of silicon, which I decided against because I don't have any problems with rubber and the Keeper is supposedly softer and easier to wrangle), I read that it can take some time to get used to insertion, removal, and the feeling of having one in. Though I need some more practice to get very efficient and proficient at folding something in half and holding it folded while shoving it up yonder, it was much easier to get in than I thought it would be at first, probably because I've been using non-applicator tampons for years. And now that it's in, I don't feel it at all. Again, that's probably because I'm used to regular-sized tampons.
To take the Keeper out, you have to pinch the bottom to break the suction holding it in place. This is rather tricky, but it didn't take me more than a couple of minutes of fussing to get right. As you probably guessed, you need to clean it before reinsertion. I find it best to rinse it with water.
Even if takes you more time to get used to inserting and removing a Keeper, it really shouldn't be a major inconvenience. The Keeper has not been associated with toxic shock syndrome, and it holds 1 ounce of fluid and the average period produces 2-4, so you don't have to empty it as often as you have to change a tampon. Many women seem to like emptying them in the morning and evening when they're at home.
And yes, it is sanitary. At the end of your cycle, you wash it with hot soapy water, and that's really about it. I don't really understand why some people get so disgusted by the idea of reusable menstrual products. Sheesh...it's just blood. o_O
In conclusion, this product seems very promising thus far. If you've been considering one, I highly recommend it.