The name, features etc, possibly slightly better specs here and there, ie crosstalk, THD at max volume etc., but usually none of it makes a bit of audible difference.

FWIW, Marantz is made by the same company as Denon.

Jason
M80 v2
VP160 v3
QS8 v2
PB13 Ultra
Denon 3808
Samsung 85" Q70