Summary: Simply the best HK has made. I am a huge fan of HK sound and have worked my way thru several of their flagship receivers including this one and previous AVR-745. No other receiver even comes close to matching the rich, warm sound that HK is known for, and the 7550HD is no exception to that legacy.
Summary: I have owned the HK AVR-7200, AVR-8000 and both of them, especially the 8000 blew the 7550 away. It has enough power but the sound quality is not all that. Also the one I had was buggy with a intermittent problem with one channel suddenly getting louder then it should.
Summary: The sound from this unit is delightful; warm, full, and LOUD if you want it. HOWEVER, unless you are a seriously dedicated digital user, this unit will seem nearly impossible to use. If you are over 40 years old, and think this will be like setting up an ordinary stereo, then get something else!
Summary: The sound quality of this HK avr7550hd is excellent--very pleasant and listenable. I have used processor out to my HK990 integrated, and the preamp and DAC are impressive. The only outboard DAC I have is a MF V-DAC but the avr7750hd's DAC is clearly superior.