I looked at the Smitty but ultimately bought the Masterflow Diabloww MF-1089. At the time it was under $120 on Amazon so was a better value. It is basically two MV-50s tied together. I have used it on one wheeling trip so far and it worked well, and is quite fast. The only thing I didn't like (other than the stupid chrome plating) was that the pressure gauge is at the chuck, not at the pump, so you have to watch the pressure at the tire, then you have to jump to the compressor quickly to turn it off.
1995 Isuzu Trooper LS