I wouldn't be surprised if the HK was the most powerful of all of them. HK states their wattage very accurately. Denon and Yamaha I believe state their wattage based only on 2 channels. Plus 10 "stated" watts is rather insignificant. I would go with the Denon, but thats only cause I'm a Denon guy (that and I can't get the fact that Yamaha also manufactures dirtbikes, ATV's, drums, etc... out of my head). Any one of those units would probably do a fabulous job.