Have a good read at the Class A amplifier site TCAAS.com. Each of the amps mentioned above and a few more feature there, each has its own characteristics.
The Hiraga is another popular amplifier.
The Hiraga is another popular amplifier.
I found that the Aleph 4 just had the edge as it has far more headroom being 100W. Bear in mind that for most listening we are only using about 5W, 50W gives a comfortable 3dB headroom.
With a lot of speakers 5W is LOUD.
With a lot of speakers 5W is LOUD.