I took a crack at using the General Midi controller for the Denon HD2500. (I'm still not sure why I can't get the settings for the Denon 4500 to work). I have to say I am very impressed with the ease of doing the mapping. I purchased VDJ a couple of years ago but have not really used in for gigs. I am going to get into it more because everything I read tells me there are lots of features that my other application doesn't have and if the Midi mapping is any indication, VDJ should be a breeze to learn.