I like the 7.5hp single phase with at least an 80 gallon tank for doing any sand blasting/sanding/painting in a home garage. I bought my IR with those specs used for $600 and had to rebuild the electric motor for $300. Its kind of hard to find a single phase motor bigger than 7.5hp, they get pretty expensive. I want to say that mine is rated at around 27 cfm @ 120psi. Whatever it is, it keeps up nicely and I can run a DA sander continuously.
Here is one kind of like mine: