Depends on what you want. We requested 4th floor close to transportation and got a nice room in the 70's section that was fairly quiet and convenient (except when they play the music starting at 9 am).
None of the preferred rooms are in the 80's or 90's section, so don't request those.
We did find ourselves going up stairs a lot, which we didn't mind so it was just myself and my nine year old daughter. If you have mobility issues or a stroller you might want a ground floor, although the buildings do have elevators. The stairs were closer to our room.
We like being on the top floor because we don't like hearing people above us.