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 
128x128lordrootman
My single ended Dennis Had Firebottle amp puts out 12 to 17wpc and weighs a massive 15lbs. Sure, it seems like I should reinforce the floor for the thing, but somehow I get by fine...15lbs...if it was dropped on your head from 10 stories above I'd want it back as hey, who the hell is dropping my amp from 10 stories up? I hate that.
@dseltz thanks for the response my 2 channel set up is including 7.1.2 HT in family living room with kids so definitely no tube amp I will be interested to add tube preamp in future 
I really love the presentation of SS and tube preamp combo 
Looking from a prospective I think a manufacturer who will implement both correctly will win at the end of the day