I run a Mygica 1600 exclusively for XBMC and I came from a WDTV 3rd gen. It's like going from a farm truck puttering the back 40 to a BMW on the autobahn. So much more this box is capable of than the old WDTV it's crazy, and I've used maybe 25% of the features.
Android itself takes a little while getting used to (4.2.2) and it's not quite as stable as a simpler streamer, but there really isn't any reason to keep cable when you have one.
The picture quality is okay - definitely liveable - but my PS3 runs circles around the Mygica in terms of PC especially in Netflix.