I recently upgraded from a Denon AVR-1909, and here are my initial thoughts on my upgrade from the 1909.
1) MultEQ XT is a really nice improvement from MultEQ.
2) Additional power is nice for driving my Infinity Cascades.
3) It's feature set is similar to the Denon AVR-2112, but the beefier power output (and heavier weight) does give it a one up on it's cousin. It also adds an additional subwoofer preout, and additional analog audio/video inputs. It is way better than the AVR-2112 in all aspects, BUT it cannot compete with the AVR-2312 for features.
1) Denon/Marantz seeme to have really cut some corners with quality since my last Denon purchase. Everyone of my "cons" is related to how the Marantz name is supposed to be of higher quality, but really does very little to give the owner this impression.
1a) My AVR-1909 came with two remotes (primary, and secondary zone remotes), but the Marantz only came with the primary remote. Also, the Marantz remote seems "cheap" and lacking in quality.
1b) Removal of the switched AC outlets is inexcusable for a "Marantz" brand.
1c) Although the "portal" display on the Marantz seems more elegant and audiophile like, it is one more way to cut cost under the guise of being elegant.
1d) For Marantz, a paper manual should be a requirement. Again, the Marantz line is supposed to be of higher quality than the Denon. Is it really worth saving a couple bucks to exclude the manual, and cheapen the Marantz experience? No.
Not a pro or a con, but I would like to point out that my old Denon AVR-1909 weighed 25.4lbs, and was rated for 90W/channel. The SR5006 weighs 25.6lbs and is rated for 100W/channel. Is the fact that the SR5006 can pump out more watts with a simlar weight a testement to a more efficient power design, or are they cutting corners again? I will give Denon/Marantz the benefit of a doubt on this one. I will go ahead and say they have a more efficient design!
In short, I don't feel a buyer should pay a premium for the Marantz name, unless you want something "between" it's Denon cousins. The SR5006 is a much better receiver than it's cousin the AVR-2112ci (more power, additional sub preout, more analog AV inputs, detachable power cord, beefier power output, heavier, etc.), but it cannot stand up to the feature set of the AVR-2312ci (video scaler, front HDMI, improved GUI, etc.). If video scaling and GUI is of no importance, but power and sound is, the SR5006 is the best choice between 2112ci, and 2113ci. It is for this reason I choose the SR5006 over the other two. The MSRP is rightfully priced somewhere between the two Denon offerings.