While there are differences in their analog circuits, if you read through any of the "bench tests" of modern quality solid-state equipment, you'll find that the measured differences and distortions are at levels which are completely inaudible to human beings when the equipment is used within its design parameters. Of course, if you have inefficient speakers in a large room and like to listen at very high sound levels, so that amplifiers are driven beyond what they were designed for, distortions quickly raise to levels which are audible. Although many people do like to listen at high volumes, most usually don't use more than about 10 Watts or so per channel when listening at comfortable sound levels.
In general, most of the quality (accuracy) of the audio you hear is due to the quality of the speakers and the acoustics of the room. Most of us can't afford the time and money to audition and purchase high quality speakers, measure the room response, and apply proper room treatments. Room EQ can do a lot to compensate for the resulting audio deficiencies.
Bass frequencies are the most difficult to compensate for. Frequencies which have wavelengths corresponding to the dimensions of the listening room form into standing waves with peaks and nulls at various places in the room, including the primary listening position. RoomEQ software can attenuate the peaks, but not fill in the nulls. (Of course, many people do get used to the "punch" delivered by those peaks, and get the feeling that accurate bass is somehow anemic. *shrug* It's easy enough to turn up the bass level if you discover you feel that way. ) With two subwoofers, however, one can be placed so its peaks fill in the nulls generated by the other, resulting in a much more uniform frequency response.
Marantz SR7009 avr + MM9000 amp --> Atmos 7.1.4
Fronts=NHT 2.9+AC2, FH+TM=DefTech PM1000, LCR+TM amped