is too large a room no good?

I am looking into a new apartment that is approximately 48' long, 18 feet/23 feet wide and 10' ceilings.

Does anyone have experience moving their system into such a large room?

I heard Greg Petans system - which are the huge Sunny Speakers in his massive 2100 sq/ft room and then the slightly larger version in Clement Perry's rather normal size room, and Clement's sounded better.

On another note, I'm almost sure the place I'm considering does not have concrete floors, since it;s a very old structure (but with no columns).

I will sorely miss the concrete floor in our old building, since no one above or below me could hear my system, and the structural stability was great.