It's a Sony CDX-GT565UP and I really like it so far.
52x4 pushes my 6 speakers perfectly.
I run the front dash and overhead speakers on the front channel and the rear channel on my small and cheap speaker box behind the rear seat. The speaker box in the back is finally getting pushed right.
I really like the feature that turns your rear speakers into subwoofers.
It basically cuts out the treble and boosts the bass. It's got a lot of different options for illumination and is Sirius/Xm ready. My wife has sallelite in her car and I like it, so I may get it soon.
I mainly got it for the usb port so I can finally have a flash drive with all my tunes on it like all the other cool kids.
Since flash drive is my main method of music, I took a flash drive with me to Best Buy so I can see how well it navigates through it and it was really quick and easy.
I have not tried the aux input on the front yet.
It can do Pandora but I get Pandora on my tv and am not too impressed with their library of music so that's no biggie to me.
Overall, I am getting better sound than ever (with no amp) and am very happy with the receiver.