Trying to choose between the 5100 and 5200 myself. Leaning toward the 5200 because it's newer and although I can still find a few brand new 5100's, the price isn't any less than I can get the 5200 for.For myself, not at all, I was answering this question...
There is almost zero benefit in mdbunting choosing the CX-A5100 over his current 3070,
and the CX-A5100 is almost 4 years old, so not even sure he would be able to find a new unit, so the 5200 is more likely available.
The Marantz pre/pro still gets my vote, if he's got the $$$$