Well, I'm a guy, but from my experience -- the only way to really go wrong with a vibe is allergy issues and hugeness. I have heard the plug-in ones can be nice because they don't lose intensity as batteries die -- so if you're not going for portability you may want to try one of those out.

And please don't feel embarrassed. No shame in wanting to enjoy oneself privately. Myself, I think it's pretty sexy!

Am I prying if I ask (generally) what career you're going into that you'll be working with this stuff regularly? You've piqued my curiosity....