Long story short: I auditioned it, bought it, set it up at home, and it sounds FANTASTIC. A/B'd with a McIntosh MA8000 and preferred the very slightly cleaner, transparent sound of the Lyngdorf. RoomPerfect brings the frequency balance right where it should be at the listening position. The amp has no trouble playing loud to provide work music in adjacent rooms, and no trouble playing quiet while still preserving all the details. I love it to death!
When I first started my dealer audition, also on Summits, the soundstage was compressed and shrouded. I was quite surprised and worried that all of the reviews were just hype. Then, after approaching the unit and reading the small screen up close, I realized it was set to the 'bass1' voicing profile. I switched it back to neutral, the highs came back, the soundstage burst open, and I got a huge stupid grin on my face because the music sounded so freakin' good! I put in about an hour on bypass, swapped in the MA8000, listened another 45 minutes or so, swapped the TDAI2170 back in, and knew right away it was the one.
I compared the amps without RoomPerfect for the first several hours and gave the nod to the Lyngdorf, but with RP switched on, things went to another level. At first, although it was clearly a different sound, I wasn't sure it was better. But, the more I listened to it, the more I listened in to the performances, the more I missed it when it was turned off. It's quite an amazing device, and with good recordings, it hasn't failed yet to put that stupid grin back on my face no matter how long the day has been. I am thoroughly and totally pleased with it. It's the cleanest, least colored sound I've had.
Impedance curves and wattage aside, give it a listen. Make sure they calibrate the RoomPerfect while you're there; it only takes 15 or 20 minutes and the difference is substantial.