I own the Marantz 7702 and would recommend the 7706 for both HT and 2 channel music. I have compared it to four different dedicated two channel preamps thinking I could improve two channel performance. The Marantz was my preferred two channel preamp as well. I use the XLR connections. If you want to get the best performance get the paid upgrade to Audyssey ($199) and the calibrated mic. Night and day difference and I prefer it over ARC room correction. You can see my 9.2.8 HT in my profile. I have a setup for both atmos and auro-3d.
I also have an Onkyo receiver in the man cave, I prefer separates for the best SQ.