An AVR will convert all of the analog inputs to digital, then use a digital volume control, digital signal processing, etc., then go back to analog for amplification. The AVR will have lots of extra output channels and you'll end up paying for that.
A proper integrated amp should be analog from the input to the output. One easy thing to look for is the presence of a motorized potentiometer for volume control rather than a rotary encoder, though the presence of a rotary encoder doesn't always mean a digital volume control. If an integrated amp without a DAC is chosen, said piece will not age out as DAC technology progresses.