Hello, chiming in again, I listened to the Mahlers extensively when deciding whether to purchase them or the Beethovens, and the Mahlers were placed on the long side of an average sized rectangle-shaped room, room no bigger than the average living room in a non-mansion. There was no bass bloat or boominess, just not as focused and detailed as I found the Beethovens' bass to be. The Mahlers were being driven by big Levinson monoblocks--333's? the newer ones, anyway. The Beethovens were being shown in a much larger room, probably twice as big, w/Ayre amplification. Ayre V-3, at 100 watts per channel. Again, no boominess or bloat.
I concluded that the Mahlers needed good, big power. And keep them away from the side walls.