Actually my use of AVR is a pre-pro for all the connectivity. Marantz pre-pro is out of my price range. I buy the factory refurb Marantz, have had good luck twice.
The Denon AVR-A10H will most likely measured a little better than the Marantz Cinema 30 because it uses better DAC ICs but if you don't know that then you will not likely hear any difference anyway. The Cinema 30 offers two selectable DAC filters that will give you two different frequency responses and distortion/noise levels, but then again those differences are theoretical, though measurable by instruments, yet there has been no evidence that humans could tell the differences but that's a different topic that I just want to mention it as there are so much misconception/hearsay based posts you may run into in your research.
If I am to choose, your approach of using a side by side comparison of the features, look, and price is a good way to base your final decision on but that's just my opinion. Final note: Use as preamp/DAC/Processor, electronically speaking, aside from the better DAC the Denon has, and the senseless HDAMs the Marantz has, the two are virtually the same. Apparently, depending on your region/country, Marantz likely offers a longer warranty, that is 5 years vs Denon's 3 years.
