As far as personal preference, I get bar soap - there are lots of different scents. Some affect the skin more than others, everyone is different on that.
Cost - bar soap is WAY cheaper, and I think each bar lasts longer, to. So you're talking about a price difference of about 10x.
As far as guests and used bar soap, I definitely hear. On the other hand, with body wash, you're using a loufa anyway, presumably? So unless you bring your own loufa, the only difference is that you can't see the hairs.