Originally Posted by maunakea
the Nexus RL 8 is significantly lighter than the S-A 7.
"S-A 7"? Edit: I'm reminded that it does exists

It's no longer listed on Sturmey-Archer's website though, so I haven't found any numbers for it.
I looked up the weights of the various hubs from the manufacturers' websites:
SRAM Spectro 7: 1556 grams (3.43 lbs)
Nexus SG-8R25 8: 1550 grams (3.41 lbs)
Sturmey-Archer XRF8: 1500 grams (3.3 lbs)
They are all very close in weight, and to be honest I doubt most people would notice a difference of 56 grams! (One might well notice differences in efficiency, but I don't have any hard numbers on this. Anecdotally, the Nexus is said to be better)