Hello! I am also facing that choice, but here in Germany the Marantz in the range price of Yamaha rx-v630 is 4300, not 5300. What about it?
And, in adition, I also say that it is worth to listen to the Harman-Kardon 2550.
I want to demo all together, but I didn't have a chance yet, so I am delaying my decision... I think they will become old if I don't hurry up!
I must say that Harman-Kardon has a very well defined sound, easy to place each intrument in space, not just coming from the speakers. Very balanced, fair sound. I found maybe too much bass on it, could be the speakers. I tested rock and classical guitar music. No chance with movies, stupid guys in the shop. One intriguing thing: it seemed that I had to push up the volume level to get some sound filling the room (small, say 5x3 meters). Could it be that I am not used to count in dB? The range goes from -80 to +10dB, as far as I remember (strange? Don't they usually go up to 0 dB?), and I was playing at -25. I know, the scale is not linear, but... Is this normal? I mean, for example the usual rule with "normal" devices (I mean, analogic), the rule is stop at 1/2 of the whole turn for good not distorted sound. I have now a SONY str-de 135, which gives 2x60 watt rms, and I even do not reach that level before my room becomes too small (it is 4x4 meters). But with this, if I take -35 dB as the middle point, I do not reach that sound level (and it is supposed to have more power than mine!). Is it just that the scale is different, or what? I also thought that they may have some device to "quench" the signal, in order to protect everything from stupid customers...