I've had my Music Hall A15.2 for over a week now, and I am very impressed. It has more than enough power for my not-very-sensitive bookshelf speakers, and the sound is terrific.
I'm not an experienced audiophile and I don't know all the lingo, but my observations are the sound is very accurate, with a fairly broad soundstage, and little coloration. Vocals are open and highs are very accurate. Bass is a tad muddy, but I think that's a function of my room. It is pretty echoey.
My source is the CD15.2 player, my interconnects are Emotiva ultra series, and my speakers are the Def tech studio monitor 350's with an Emotive Ultra 12 subwoofer.
Compared to the Onkyo A-5VL, the sound is much warmer, much more open, and less fatiguing when listening at louder volumes for longer periods of time.
My other means of comparison is to "my" reference system (McIntosh separates with B&W 803's at my local dealer
The short version: I can highly recommend the a15.2, and compared to the Onkyo I tried before it, well, there is no comparison.
Edit: Forgot to add some other thoughts about the physical aspects of the a15.2. Build quality is solid, but not as hefty as the Onkyo or other Marantz products i have owned. I do love the understated and simple aesthetics of the unit, and i appreciate that the remote is fully functional (as opposed to the onkyo which literally only controlled volume). However, the remote is probably the cheapest remote i have seen in years. I would guess it came from a cheap 19" CRT tv from walmart in 1990 instead of a piece of high end a audio gear. I know the remote is not the most important aspect, but i appreciate companies that spend some time on the details (seen emotiva's remotes?). Connectivity on the back of the unit is a little cramped, but workable. The unit does not generate a lot of heat, even when i forget to open the cabinet door, which is nice.
About the cd15.2 player: it cannot handle even the slightest scratches on discs. Even a few brand new discs i have skip. Could be a problem with my unit. I'll be sending it back and ordering a DAC25.3 instead.