I hate the Hitachi. It's huge, heavy, isn't water proof, too big to avoid vibrating my ENTIRE crotch, numbing, it overheats quickly, and is completely unsexy. I just don't get it. It's even annoying to clean. I'd prefer to use a thoughtfully designed silicone vibe, than a giant back massager, but all its flaws just don't seem to bother anyone, which is a phenomenon completely specific to the Hitachi.
Honestly, ladies, it's like buying a washing machine just because it gets you off.