I've finally had a chance to audition a SR7005 head-to-head against SR6006 in my home. For speakers, I have the Amperion Grand Verus (GV) Towers, GV Center, GV Bookshelves (for surrounds), and their 12D sub. I used Audyssey on both receivers which always makes a HUGE difference.
I agree with Kjenkins that the 7005 does sound a bit fuller. Even at lower volumes. I don't think it's necessarily power related. It just has more of a subtle dynamic sound kick. It may be the 7005 has the HDAM and high current (?) features that are otherwise only found in their high-end reference series. I really don't understand the technology or if that would explain any sound difference.
The SR6006 sounds great, too. It stands out against anything else I have heard at that price point. If I didn't have it right next to the 7005, I wouldn't notice anything lacking and would never think twice about having it. I also have to factor in the Aperion speakers are outstanding and may be able to discern subtle differences which may not be as noticeable in other speaker lines.
I agree with M. Zilch that the flip down panel is useful. Is it worth hundreds more for a little convenience? Probably not. If you ONLY had the flip down display, it would drive you nuts w/o the on-screen menus. The flip-down just adds a little information if you like seeing inputs and outputs. And is especially comforting for monitoring firmware updates. I do like the the general Marantz marketing that their small display just says "I'm about sound and no frills needed." (terrible paraphrase) With decent on-screen menus, the star porthole replaces an expensive dot-matrix displays and allows them to bring the cost down on the units significantly. You get more receiver quality sound for your buck.
So bottom line, the 7005 is a much more complete package. It does everything I could think anyone home user would need in a receiver. (And makes me wonder who actually needs or uses all these features.) I never even heard of wide-stage and vertical height speakers before hooking this up. Is that a 9.1 system? Oh wait, it has 2 sub pre-outs so make that 9.2. I have a big 18x30 ft living room and I am only using maybe half the power of the system when I have everything cranked up to the loudest tolerable level. I can't imagine how big of living room you have to need 9 speakers and 2 subs. Maybe it's not for home set-ups. (Or at least not for California sized-home set-ups.)
Along those lines, I really won't use much beyond the standard 5.1 set-up. Hook-up wise, the SR5006 would be more than sufficient for my needs. I don't have multiple zones or external amps. And I just have DirecTV and a blu-ray player. So most of the connections on the back of my 7005 are not being used and probably won't be. Although now I'm thinking that a 2nd zone might not be too bad...hmmm.
With the 5006/6006, I think Marantz worked hard to figure out what they could take out of the 7005 to reduce the cost. Maybe they realized that most users are like me who don't need ~96 various connections on the back. They did a good job. Especially the 5006 which I think would meet the needs of the majority of consumers with just the critical connections like front pre-outs and 2 sub-preouts. How many people will have external amps on their surround speakers?.
So it's a philosophical issue. Do you want what you need OR do you want somewhat negligible better sound with a ridiculous number of extra things you don't need?
If you can get one of the few remaining 7005 for about the same price as a 6006, go for it. I wouldn't have buyers remorse for the 6006. It is the best receiver I've heard at that price point and is far superior to Denon which I also auditioned and found flat sounding. I was a very loyal Denon fan with my Denon 2805 for several years, but the current Denon models' quality and sound has gone down. And Denon lost my business with their continued dedication to 1980s on-screen graphics. Come on guys.
Finally, I'm guessing there WON'T be a 7006. I see the 7005 as the full-featured prototype for the 5006/6006. What could they possibly add in a 7006 that would make it stand out against the 7005? Audiophiles speak up if you disagree. I can't think of anything.
Enjoy the sound...