Definitely a step up from the Sx 315.The sound is awesome!Having the ability to connect all the hdmi components to it is a huge plus.Used the Mcacc to calibrate the speakers and it did a very nice job.
There is one small caveat,the roku works fine with anything that is 5.1 sound via hdmi however,you will get no sound with anything that is stereo only.I was able to get around that issue by connecting the composite cable of the roku to the analog port on the 522k.Read a few posts on the roku forums about that,there was at least one poster that traded the Pioneer for a Yamaha because of that.If they will cpme over to satguys I'll show them how to solve the problem without trading receivers.
Overall,I'm so far very pleased with the upgrade.I was on the fence between 5 different models and ultimately got the best deal on the VSX 522 $125 shipped.Missed out on an Onkyo TX Sr 313 for $1 less but,in the end I think it was for the best.