Congrats! And I have to say it, you've made a great choice, whether it is for your main or secondary system. I sent my 3400 back to get a 4400 only because once I decided to use it in my HT system instead of a 2 channel music only system, I wanted to be able to try Atmos eventually. Also, since it is a replacement for my 11.2 AV8801, it seems more logical to go with the 4400.
The 3400 has great sound quality, ran cooler than the 4400, and is incredibly powerful, relatively speaking. I am sure you have much better discerning hearing than I, for me it sounded as good as my A21/840E. It is an amazing 25 lbs AVR, as long as it's not pushed too close to its power output limit, it could be a viable alternative to integrated or small separates used in a music only stereo system, to some people anyway. Oh, and for a change, I got it for under C$740 (US$560) brand new from Bestbuy after price matched, that's a better deal than many in the US. I really missed that little thing, should have kept it for spare.