I think the differences in calibration algorithms are overblown, as long as you have an autocalibration feature you're fine.
As far as those receivers goes, unless you have a space restriction need for the slimline Marantz I'd go with the Yamaha for the extra 30 wpc. While that's only about the equivalent of one notch of "louder", I just recently returned* a 1602 and replaced it with a 671 and found the sound significantly better on the Yamaha. Obviously that's subjective, and it could have been due to circuitry, not power; but given that the two cost about the same and have prety much the same features, why not get the extra bump.
* I returned it because the DLNA on the 1602 wasn't working correctly. But I was pretty shocked and happy when the replacement receiver sounded better.