What skiwagon said is right on. Anyone who is pretty serious and consistent with cycling would recognize the clear advantage of the hitch. I'd get mostly props on a cycling forum, though I know some of us here are cyclists and so I'm glad to post it on a BM forum.
It is barely noticeable when the rack is off. It actually looks pretty cool to the extent you can even see it -- similar diam to the exhaust pipes.
Keep in mind, anyone without the xi option is going to have to find a pretty competent hitch place who can do the custom engineering (i.e. I wouldn't take it to U-Haul, as I don't think they'd be qualified).
Oh, on the fold-down seats -- if I had that option on my car I might use, but I note that the used BMs with fold-down seats had really marred-up trim in the backseat from stuff bumping around. I also prefer keeping the bike behind the car, and not on top or inside.