As long as an audio amplifier is used well under its limits, it sounds good to me. Except for cheap little amps that have excessive zero-crossing distortion, I find this to be true of most amplifiers. Where they start to get weird is when they are pushed hard. Most amps sound bad when they get close to clipping but some are milder than others and some are downright harsh.

I have been particularly fond of the late seventies Yamaha amps using integrated circuit outputs. I also like NAD amps. For all out power, Crown makes great gear. On the smaller end, the National 3875 is a good chip amp. Be sure the power supply provides enough current for full output without a lot of voltage drop and use a lot of capacitance to keep load ripple down to a minimum.