Since I'm sort of spread out, I have two twenty gallon 4 HP compressors located apart instead of one "big" one. The money investment would be about the same as one big one.
(Maybe a little more)
Except I've got redundancy, can hook up either place, use one to "repair" the other if necessary and hook them together for twice the capacity if needed.
(Air line verses voltage drop if you used a long extension cord)
Like for sand blasting and running high volume air.
Just throwing that out there.
I think electric is the way to go for most of us on the sanding thing.
Except that gets a little dicey if you are wet sanding.