I am using a Denon x5200w with a few Emotiva amps for my Atmos setup and it works amazingly. I am running 13 conencted speakers; 7.1.4 for Atmos using Top Fronts and Top Rears and then I have wides connected for DTS Neo and Audyssey DSX but I never seem to use either of those modes. Dolby Atmos is legit and even the Dolby Surround Upmix adds new life to my bluray collection.
They only have one or two HDCP 2.2 compliant ports which are limited to 10Gbps just like HDMI 1.4. Meaning they are not capable of full 4k @ 60fps with 4:4:4 Chroma. This limitation is due to the chipsets available for the 2014 models; One has full HDMi 2.0 18Gbps capabilities but no HDCP 2.2HDCP 2.2 has not even been chosen as the defacto replacement for current HDCP and no devices currently use it. It is likely HDCP 2.2 (or 2.3, 2.4, etc) will be implemented once 4K Bluray players hit but that still remains to be seen. The 2015 Crop of AVRs will likely have ports capable of full 18Gbps as well as HDCP 2.2 as that chip now exists. Having said that, it is likely any 4k Bluray player will have two HDMI outs (at least any that I would buy) and you can use one for audio out to an AVR and one for the Video out to your HDCP 2.2 compliant display. I currently have 2 Samsung 4K TVs hooked up through 2 2014 Denon AVRs (s900w and x5200w) with no issues. Any 4K content is distrubuted via built in TV Apps or Samsung's UHD Drive, neither of which require HDCP 2.2 at the moment.
