I have one and I've used it several times with the Providers...it seems that the girls that have a more outgoing, balls-to-the-wall, let's PARTY attitude are the ones that enjoy it the most. And some of them REALLY ENJOYED IT...but it's not for all the girls. It can be a little intimidating and some of the girls just didn't even want to try it. It's a powerful toy; I can think of only two girls who "cranked it up to 10". The only downside to it is while she's playing with it, you're not "going at it" with her.
I usually put it on the bed, she sits on it, I stand up in front of her and get a BBBJ while she's riding it. HELL YEAH! I'm sure you've been to the Sybian website:
www.sybian.com; it comes with various sizes of inserts and yep, it ain't cheap ($1,350 I think)
The two of you (or 3 or 4!) can have a wild time with it. For the ladies, it is the ultimate sex toy. If your lady friend is in to toys, get one. If you ever want to sell it, it won't last 10 minutes on Craig's List. The website is the only place you can buy a new one.
Any questions, fire away...