I own a new Hudy and a recent Integy (aluminum arms) model. The only measurement that did not agree when I compared measurements on the same car was toe angle. The Hudy has higher accuracy ( the Integy was up to 1/2 a degree off).
The Integy has the vertical flat bar for measuring caster angle, which the Hudy does not have in its set up system.
I am no expert with these systems, that is what I found last week.
"Yellow Jacket" Mugen MTX-6, Picco Torque
TeamNITRO RC Club, Lynwood, Illinois