Keefer, that headunit does NOT have 6-channel output. It has 3 pair of 4V RCA preouts. Front, Rear and Subwoofer. 4.1 audio. It's the norm.
First off, the wouldn't put much stock into that "top 10" website you linked to. They have a headunit made by Boss in their top 10, scoring a 9.4 out of 10 at that. Everything Boss makes is cheap swap meet garbage. Ask anyone in car audio for yourself. Second, they rate the "installation" of the headunit. THEY'RE ALL EXACTLY THE SAME! They give it points for being "DIN sized"?!?! Newsflash, every headunit is DIN or double-DIN sized! That website was written by a friggin moron.
It's tough to get a high-end headunit with many audio options (multi-band EQ, time alignment, High and Low Pass crossovers, etc) but yet not have HD Radio or Pandora options. All those extra features are included on higher-end headunits. It's like asking for power windows, but not power locks. It comes with the package man. I recommend the Pioneer DEH-P7400HD. $125 shipped from Amazon. Extremely tough to beat, especially at that price.
HD Radio works exactly like a normal FM tuner. You won't have to do anything different. You won't even know you're using it, other than having more clear FM stations. No reason not to have it if it's included. And the display and buttons can change to any color you want. You can even have it scroll through all of them if you're into that disco color scheme.