I have the Hitachi, and I like it - but only if I use it with the Hitachi wand Controller, which allows you to adjust the speeds. It's WAY too strong for me to use otherwise, now.
When I first got it, it just hurt and would take me a LONG time to reach orgasm, but when I got there, it was so intense and would last forever. Now, I use the controller and it's a lot more comfortable and awesome to me. I don't even use it without.