Yes, absolutely true. They love power/current, but the smaller models can't play loud, a bit of a conundrum indeed. Like I said, I've owned 5 pairs (MMG, 1.6, 1.7, 3.6 and lastly, 3.7's). I enjoyed my time, but I went nuts constantly adjusting them due to the tiny sweet spot. Bass has a bit of a "plastic" sound I always found as well.
But look, setup right, playing classical music perhaps, in the right room, right electronics, the 30.7's can do some things very well I'm sure. I just think it's best to demo speakers in a proper seating position. Everyone can share the sweet spot, it's ok, they'll live.
I know Jim Smith advocates finding the best seating position FIRST, then dial in the speakers. I do too. When the demo is "no chairs allowed, go walk around", I don't know if that's the best approach. Reflections off the ceiling are a real problem and actually create time delay issues. I tried to explain this to the powers that be at the demo, but was told, "if you want a use a chair to stand on, that would be ok, but not to sit on." I'm not sure what the point was. It's so hard to focus on what's going on when the high frequencies are reflecting off the ceiling and singeing your ears off. As you can see by the picture, I'm not a good listener. In the chair, I was able to get a much better idea of what the speakers can do and not do. I had a hard time with the very over sized imaging, as others have mentioned above. Again, could be setup, don't know.