I have one of those $400-500 units and it does OK for light air tool use
but not quite enough capacity for hogs such as an orbital sander or
light sand blasting after about 5 minutes of continuous use water
droplets begin to bypass the water separator/filter and show up at the
tools exhaust and also plugs up the sand blast nozzle. Spoke with an air
compressor expert from one of the Internet stores that features
compressed air filtering, water separation etc and this fellow said if
water droplets are bypassing the filtering units then the air compressor
is cycling longer than it was designed for, i.e. compressor is under
sized. If I had to do it over again the $800 units would be an entry
level purchase and I would even consider the 1500 ones because doing it
right the first time is cheaper in the long run. PS don't believe
anything printed on the sides of the A/C at the DIY stores such as
output ratings, I have seen identical units but just painted different
color schemes state different outputs. They have already been labeled
for false representation of their HP ratings . BELIEVE IT NOT BUT
INGERSOL RAND HAS GOT SOME REASONABLY PRICED UNITS WITH CONSERVATIVE RATINGS