After using Tony's in Moab, I bought one of these.
http://www.quadratec.com/products/95202_402.htm
I have used that for about 4 years and it works great. You do have to bend down usually sit on a bucket or something.
I thought the Staun/Smitty's were pretty cool but after watching a guy screw one on and it took his tire down to about 0 psi and the pain of airing it back up...I decided to continue using my manual Currie...and the Currie unit is fast.
That can happen! Happened to me once when they froze up when I was pulling that Tractor Trailer last year and I was almost on the rims before I realized it but I don't normally air down in the snow and ice lol.
It can also happen if you don't take care of them, maintain them, if they get dirty. If they are clean, a shot of wd 40 keeps them working great but if they are dirty with sand and grit, they come apart easily, and you have to calibrate each of them again to the pressure you want.
I have both and never use the hose/stem pull one.