I upgraded from an Onkyo 606 that had served me well (after soldering new caps on the HDMI board) and wanted to go with something that had networking capabilities as well as 3D capability. I also found it nice to be able to use the airplay but at the time we were mostly iphone people. Since then, we've switched to Androids and I don't have an easy way of streaming music wirelessly to the receiver. We mostly use Spotify for listening to music. I also find it difficult to determine what surround mode the receiver is in half the time when watching movies because it always says "Auto".
Another thing is I expected to hear a some kind of difference in sound quality when going from the Onkyo to the Marantz but I have yet to notice it, maybe my hearing isn't the best? So now I'm trying to decide if it's worth it to upgrade to the Marantz that supports spotify and sell my current one, or try a different brand with a little more android support and better app since I apparently can't notice a difference in sound quality. I feel like the whole networking part of this receiver is worthless because there isn't an official app that supports the 5006 and the stuff provided built-in isn't useful to me (internet radio, pandora).