Best of Both Worlds
BACKGROUND:
I wanted an AVR that had superb dual HT & 2 channel abilities without spending an arm an leg.

As we all know, AVR's depreciate quickly due to constantly new technologies be introduced & within a few years your HT AVR is middle-aged.

I researched, auditioned & owned all the mid-level usual suspects: Denon, Yamaha, Onkyo has more gadgets...but couldn't really match the Marantz in 2 channel. NAD sounded equal to Marantz, but spartan on features, more expensive and has reputation problem with reliability.

I intentionally purchased the 6004 "refurbished" to not only save money, but most of all, hearing about reliability issues (pop of death), I knew refurbished products go through an additional quality check which gave me some peace of mind on this purchase.

THE SOUND
2 channel (stereo) - is indeed superb, highs to lows well balanced, very smooth sound AVR, however did find bass a little boomy sometimes. I also own a well regarded 2 channel tube amp costing double the price of the Marantz, and that tube amp itself competes against amps 2x it's price. My tube amp was ever so more liquid/organic sounding, but was surprised how close the 6004 compared. In fact, the 6004 had deeper, tighter bass than my tube amp and because I bi-amped my speakers with the Marantz, I found the marantz's imaging was actually a little better than my tube amp.

HT abilities - as my room is considered a small room (18x12), I found the 6004 drove my 4ohm speakers to descent levels, never did I feel the amp "ran out of gas". Watching & listening to blurays was always enjoyable. 6004 had no problems/lags when switching to different inputs and recognizing souce.

WHAT I DIDN'T LIKE
- HDMI video outputs cannot be used simultaneously (there are 2)
- Audissey is more of a guideline to help setup your system...didn't find it that accurate
- Audissey db settings are "memorized" even for pure direct mode which defeats the purpose of pure direct mode.
- bluetooth adapter sound quality more for convenience. sound quality sucked.

WHAT I LIKED
- usb music sounds great especially with "mdax" feature
- handsome looking receiver
- no useless s-vhs inputs people would never use
- flexibility of inputs, however, would have LIKED an ethernet connection for DLNA capabiltiies

I had the AVR for only 2 months, so cannot vouch for reliability yet, but I been using it daily without any hiccups. Though I believe there maybe some issues with some 6004. I'm suspicious why someone would continually bad mouth the amp and continue to own a 2nd, 3rd, 4th, 5th replacement? Most people, would have left any product after 2 duds.

Associated equipment: PS3, Xbox, Apple Airport Express, WD Live, Totem Arro/Dreamcatcher surround speakers

Marantz SR6004 - Fantastic but misunderstood Receiver
To start off, for those of you that don't know, Marantz and Denon are sister companies under the same umbrella (D&M) sharing some of the same technology, directly competing against each other. That being said, I own both a Denon 3800 series and the Marantz SR6004. Both are very solid performers, performing well above their price points. For my tastes the Marantz is sonically superior to the Denon - barely. The Marantz setup is pretty straightforward and its handling of content is wonderful, although not as flexible as many of the receivers in this catagory, the person that buys the Marantz is looking for sound quality at an exceptional price point, not gagdetry. The Marantz also does a superb job with video as well, doing an excellent job with non-BD as well as BD material, colors just popped whether through my Sharp 52" LED TV or my Panasonic PT-AE4000U 1080p projector. The one issue I am currently struggling with though is the second HDMI out. Does not seem to flow any data through. Have contacted Marantz and am currently waiting for an answer. I suspect the owners having larger problems with their receiver may have bought from or may have inadvertently received a gray market item. Marantz as well as Denon both have had reputations for building solid products for years, seems odd that the SR5004 and SR6004 would stray given the pedigree of the companies under the D&M umbrella.

Unstable - Useless RMA process from Marantz - Stay Away!
This unit and the SR5004 ( Marantz SR5004 Audio/video Receiver (Black)) are to avoid: I bought one in France in November and unfortunately the unit fails as described here: [...]

Issue description: the unit switches off randomly approximately 10 times a week. It requires a complex combination of keys to be restarted. The issue happens even with very simple setups (1 SPDIF input,no HDMI, 192K stereo) , at very low volume...

As many owner experiencing the issue I sent the unit back to RMA, it came back one month later with the issue unsolved, a note saying "check the setup".
Marantz is not dealing with the issue or communicating on it, which I interpret as a fantastic contempt for their consumers. Especially for a brand building its sales speech on quality...

Conclusion: the sound quality is not worth the headache 1. dealing with the unit instability 2. dealing with Marantz to try to fix it.

Excellent reciever for your A/V and Music Needs!
I've read plenty positive and negative about this reciever. After talking to my local salesperson he convinced me to take the plunge. His input was that "according to Marantz the return rate on this reciever is 0.25%." I don't know that this number is truly accurate but my dealer is an "Authorized Showcase Reference Dealer." I don't specifically know what this means but according to Marantz customer service this is quite an achievement; so I feel confident in my purchase and any options.

I can say that after 20 hours of "play-time" I've got nothing but praise for my newest audio/video purchase.

Enough talk and into performance...

I've got this set up with a full Emotiva speaker setup, Oppo Blu-Ray, Nintendo Wii and Sony HDTV.

There is no noticable loss of picture quality when routing the HDTV signal through the reciever. Sound quality is excellent. Detail is fully captured. The upscaling from non-1080 isn't perfect but no upscaling is from what I've seen. You're gonna have a hard time adding what isn't there so this isn't a concern, just an observation.

It has a ton of set-up options which are good for someone like me(an audio/video tweaker) but could be bad for someone craving simplicity. If you're really into simplicity you should probably just buy an HTIB. The auto-setup works okay but left a bit to be desired with the subwoofer. Again, this is usually the case when using autocalibration. I used my trusty sound pressure meter to make some adjustments.

The audio profile is very good. Nice imaging across all speakers when listening to to music, soundtracks, etc. There are numerous EQ options which allow you to (nearly) infinitely tweak the music to your taste. It provides a nice soundstage for SACD, HDCD, DVD-Audio, Blu-Ray Audio et. al. Really nice for an "A/V" reciever. The ability to bi-amp my front main left and right speakers is a great addition and really does make a positive difference in regard to left/right sound quality.

My biggest gripe is with the auto-setup as it doesn't do a good job of recognizing the subwoofer. Although I suppose if I had a bit nicer sub it may have done a better job. It "auto-set" the crossover at 140 Hz which is way to high and led to a very "bass-ey" response until remdied. Small potatoes as I easily fixed the problem manually.

I would have liked a phono stage but I should probably have a separate amp for my turntable anyway so it's another small complaint.

Highly recommended as a solid A/V reciever for a nice HD setup needing a great soundstage and central routing. I upgraded from a 10 year old reciever lacking HDMI and reduced the amount of cables from 40+ to 15 (including speaker wire). Highly recommended!

Dont waste your time with this
All these reviews of these receivers going bad are TRUE. The same thing happened to me, I've gone through two of these units and finally returned it for a Denon 3310ci. Just because your unit did not go bad does not mean we are liars, all it means you got lucky with a good unit. Why would so many people make up the same story? Think about it! Do you honestly think we are all out to get Marantz? LOL The sad truth is there is a significant batch of these units that have a design flaw where there is a HDMI voltage issue when used with a cable receiver. My dealer spoke with Marantz and after some teeth pulling they finally admitted there is a REAL issue. Unfortunately Marantz is not handling it with class and is telling just about everyone that calls that they have never heard of this issue before. They need to stop trying to downsize the problem and come forward with a recall. This is pissing off alot of people and they are losing alot of customers including myself.

BTW the Denon 3310ci is an awesome receiver, sounds just as good if not better than this and the video processing kills this not to mention it's network and internet radio capable. So if anyone is considering this receiver dont take your chances. Fork up another 0 and get the 3310ci, you will not be dissapointed.