what are you going to be using it for?
I have a 6.5 hp on a 60gal DeVilbiss 2 cylinder, single stage (125 psi)
its rated at 9.4 scfm @ 90 psi and 11.9 scfm @ 40 psi
if you are using good quality air tools, it seems to keep up OK
cheap tools use a lot more air volume