I got my STI Driver upgraded to the STI Magnum and last weekend I had the chance to try it out. My upgrade entailed Updated software and repaired antenna.
I traveled from Ottawa to Toronto and back along the 401 and with the OPP using K-Band radar the STI Magnum alerted me every time with with plenty of opportunity to slow down and pass the cop at a decent speed. The ramp up was excellent and the stealth-ability of the unit is excellent as I left it on the entire time and the fuzz never batted an eye towards me.
Overall I can't complain about my unit.