I think the last sentence is the key here. I have tried all my basses before buying, so I already know I like something about them and that there isn't a problem that keeps me from buying. So, at latest for me, maybe it is the ergonomics, or maybe it isn't but all my basses work for me.
I have tried a number of Fenders. They don't speak to me (except that made in Mexico P I tried a few weeks back, but it was just OK). Likewise, I have tried a few Rics and they just don't speak to me. I even tried a Yamaha 305 that I really wanted to like (it looked great and the price was fantastic), but it just didn't speak to me. I have liked all the Ibanez that I have tried but haven't gotten around to buying one (yet).
Although, I have tried one of these
Gretsch Guitars - G2220 Junior Jet Bass II, Rosewood Fingerboard, 30.3'' Scale - Walnut Stain
and Gretsch is a 7ender brand... These play really nice and I think it is lot of bass for C$400. Could end up with one as the office bass.