All I've been to are incalls in condos. It's the SP's "territory", so I would assume they're the most comfortable there.
Me being a shy, self concious, poor self image individual, I would be rather tense in any situation, so any enviroment would be the same to me. But I am learning to put that out of my head. Not easy, but I'm getting there.
The other upside of a condo is that it also has a livingroom. Odd I know, but let me carry on. This lets you socialize a bit in a little more comfortable enviroment. It lets your anxiety settle a bit before the main event. And I find the pregame chats to be very enjoyable and relaxing. Where as I find even the thought of socializing sitting on the edge of bed with attractive woman raises my anxiety. Part of it is how I've been conditioned though.