I vote for the ground floor. The stairs get harder and harder to use as time goes on. I have a sewing room upstairs and one downstairs. My cutting table is upstairs. When I'm up there, I stay up there and I have to be very careful coming down the stairs. I can no longer just go up and down like it's nothing, and I do have to hold on tightly as I come down. Again, downstairs would be my vote.