For a rear wheel – SS hub, mavic 521 rim. Which one and why? Thanks!

Why use light spokes with a heavy rim?

Aye. Seems silly.

Comp all the way.

Using revolutions would be like sticking 2.1″ semi slicks on a DH bike. Or something.

Yeah as above. Rev spokes really are significantly thinner and much more fragile.

GeForce Jumky – I wouldn’t call them fragile but they simply won’t build as stiff a wheel (no matter what anyone says) go DB unless you weigh **** all (but then why would you be choosing 521s?)

I’m choosing d521 as that’s what I already have and as I like fatter tyres I can’t see a point in x317s. I never had any Revs so that’s why I asked, thanks.
BTW Are there any other spokes that are good, strong, silver and cheap?

Don’t know about cheap but the Sapim Race are just as good as the DT Comps. As above, no need for the Revs on that build.

Revs are strictly for XC jeyboy/weight weenie applications, are more tricky to build with because they twist more, and as the others have said you’d be wasting you time and money pairing them with D521s

ACI Alpina DB spokes are cheaper than DT and just as good IME