I bought a pair of those Origin8 drop bar ends and installed them on a typical MTB riser bar for one long ride (2 hours or so) just before I did my drop bar conversion.

My opinions:

1. Too wide
2. Stock brakes and shifters were too far away from my hands
3. No "hoods" position with stock MTB brakes
4. They looked really strange with the riser bar

But...

5. They got me down in the drops when riding into a headwind and when I wanted a different hand position.

So they sold me on the concept of drop bars, but I wasn't happy with them alone. I went ahead and bought a new stem, drop bars, brake levers, and shifters.

I have no regrets about doing the full conversion, nor of buying these drop bar ends to make sure that's what I really wanted to do with my MTB before spending a couple hundred bucks.

For what it's worth, I had them for sale on the Denver craigslist for a month asking $10 cash with no inquiries. I guess these aren't in great demand, or my price was too high. I'll probably donate them to the bike co-op the next time I'm over that way.