As far as technologies, topologies, and power output ranges go, I think there are great and not so great amplifiers of every type.
I've had many highly regarded amps, and I can tell you two that sounded best to me.
Sansui AU-7700 Integrated Amp Very clean and detailed, early to mid 1970's, about 50 W/ch*. Sansui knew what they were doing.
Alesis Matica 500 Power Amp 125 W/ch* , 80 V/usec I think this high a slew rate tributes to the sonic excellence of this one.
*Rated power outputs at 8 ohms nominal load impedance
Evaluations when listening with JBL 4410 and JBL 4412 monitors.