Here are some thoughts from an owner of a 2010 Onkyo HT-s6300 (similar build, just less features and short front speakers)...
Onkyo receivers are well known for running hot. Mine does and I assume that this one does as well (I haven't seen any reviews that state yes/no). You should always have plenty of ventilation around the receiver.
Comes with a plug-in microphone for automatically leveling the speakers custom to your room. This actually works very well.
All of the input combinations are customizable (optical, coaxial, hdmi, video) and nameable in the onkyo gui. You don't get this on lower priced (non onkyo) receivers.
This model has analog upscaling to hdmi!!! That was the reason that I spent the extra on my home theatre in a box (HTIB) when I bought mine. The lower priced Onkyo HTIBs do not offer this! Finally, you can connect your older components with composite video to the onkyo receiver and have ONLY ONE HDMI CABLE going to your TV (ie with an Xbox classic, VCR, or Wii). In my mind, this is a fantastic and worthwhile feature of this box.
I have the same exact subwoofer unit. Just a heads-up that there is no protection over the subwoofer speaker cone, which is on the bottom side of the unit. Not that you'll have to worry about this while the unit is in use, but something to consider if you expect to be frequently moving it or if you have small children...