I heard them all, no damn difference, unless you are under the Placebo effect. 7010 costs more when brand new because it is Marantz's flag ship AVR. The 4200 (now 4300) was Denon's 3rd in the lineup, below the 6200 (now 6300) and the flag ship 7200 (7300 not out yet). Between the 4300 and 7010 I would definitely take the 4300, but between the 4200 and 7010 I would take the 7010.
If you need multi channel analog inputs then you have to go with Marantz.