I love my Hitachi and the orgasms it gives me, but I disagree that it's "the only vibe you'll ever need." It's too powerful for constant use; I managed to use it for 10 minutes before coming the other night, and for the next half hour or so my vulva had that tingling sensation you get when your feet fall asleep! It didn't hurt, it was just ODD.
I also like to draw my play sessions out. I'm a single orgasm kind of gal, so using a powerhouse like the Hitachi doesn't always bode well for me.
And of course, there are those times where the Hitachi is too powerful or it just doesn't seem to do the trick and I can't orgasm at all.
Also, I hate that the head of the Hitachi isn't 100% sterile. I have to use condoms with my Hitachi, and it's a pain to rinse it off when I'm done.