Amplifiers weight

What does amplifiers weight has to do with performance?
im trying to decide between this 3 amps
parasound JC5 73 pounds, Anthem STR 60 pounds Michi S5 by Rotel 132 pounds 
I can get them around the same price 
my speakers is modified klipsch KLF 30
preamp is Michi P5 and a pair of SVS SB16 ultra Sony Hap Z1 and Cambridge Azur 851N
i really like the looks of STR amp 
Weight has nothing to do with anything unless you are carrying it up 3-4 flights of stairs. So either buy a lighter amp or work out more. 
I have never heard a class d amp, or for that matter, a Rotel, sound musically engaging. Get the Anthem or Parasound. I love my 65 lb Luxman class A!
Regarding the Michi:

Honestly, I would never buy any solid state amp that needs 2 fans to keep it cool.
Thanks @cakyol , that was an interesting read.
Pass’ thoughts on weight vs. power and amplifier class, and the benefits of a suitably large power supply, seem logical but from the standpoint of sound quality there must be more to it since he continues to design new amplifier lines that apparently sound different/better than his previous amplifiers.