As much as the upstairs room sounds nicer, I would probably go with the first floor room. For all of the reasons stated here. Unfortunately we aren't getting any younger. Mine is upstairs because we have 5 bedrooms up there. The master is on the first floor. I will probably be scheduling knee replacement surgery next week. An advantage of being upstairs is that you can be left alone if you want to be. Also I can leave a huge mess, which is the norm. I will move into the dining room if I have to.
The grandkids and guests will have some privacy upstairs.