Damned good! Regarding power, I drive mine with Ayre AX-7e (60 watts) to great affect tho' I cannot reproduce concert levels of The Who. I love the combo. Regarding room size, mine is considerably larger (18x19' with a vaulted ceiling) but I have heard 3A Sigs in a room about your size and I thought it sounded fine, excellent, in fact. IMO, you need to keep them away from the front (and sides) wall by >3' and also need to be able to sit about 8' away. In my room, the listening position is against the rear wall tho' I also have an opening to the next room behind me. When I heard those 3As, the listening position was also against the rear wall with the speakers about 3' from the front wall. Good luck.