I know this is a very old thread, but since I own Parasound Halo and just bought a pair of Anthem M1's due to the very appealing size, efficiency and beautiful craftsmanship, I thought I'd make some comments.
First off; the room: 10,000 cubic feet of space with an 18 foot vaulted ceiling. The main speakers: Bryston Model T's with two new subwoofers from Axiom Audio (A custom modified amplifier from Ian to test a new design in the EP800 and the other is the EP500).
The Parasound was used to bi-amp the Brystons with 400 watts going to each section of the speakers. Frankly, it sounded very good but was running out of gas under heavy loads. The Brystons love power and a lot of it. So I decided to try out the Anthem M1 mono blocks as they can easily put out 2000 watts per channel continuous when wired with dedicated 240 V/15 amp mains, which I did. I initially set them up on 120 volt mains, but did the work to get them full power.
My initial observations: When I installed the M1's on 120 volt mains, they blew away the Parasound in all respects. FAR more power, much more detailed in all frequency ranges and an amazing sound stage. But when I went to 240 volt mains, yikes!! It's like being at a live concert, the triple woofers in each Bryston T have almost as much low end output as my subs! It was like adding in two more subs to the room. I am hearing specific instruments which I didn't hear before. I have no idea why anyone says that class D amps lack in the upper frequency ranges, NOPE, they are fabulous. Plus the Anthem M1 does not use the ICE or any other off the shelf power module, they did a complete ground up proprietary design. I think they got it right. And I love the liquid cooling with copper heat pipes.
Speaking of, these amps never get over 95 degrees, they are only at a warm room temperature (summer temps).
If you like the Parasound Halo series amps, you'll really love the Anthem M1's, they are in a different league. They are so nice that I actually spent the weekend custom machining dual front handles which mount the amps stacked on top of each other with 1.25 inches of open space between for air flow and to hold the amps in a single space which is still more compact than the Parasound. The M1's are so rugged with the heavy aluminum front and side plates (all bolted parts), that when I bolt them to the handles, the two amps are free suspended with no other support!
Very impressed, very. And I really like that they only consume 2 watts when in standby and 33 watts when idle. Again, as I say, there is minimal heat given off vs. the Parasound which could lightly fry an egg in a pan on it.
Pay no attention to the audio reviews; listen to these yourself and make your own decision; it was easy for me, these are keepers.