diff in the two? is the pro worth the diff in price? thoughts>?
the pro is slightly more accurate with an additional 2 strain gauges. from talking with the SRM folks about this over the years it seems that the pro is predisposed to having fewer functioning problems than is the am. But you can’t go wrong with either, it’s the best training tool out there.
couple of thoughts on the two…
I started wattagetraining with the am, and quickly went to a pro. there was no hugh jump in my numbers upon doing so. but one of my main reasons for the upgrade (besides the ww in me) was that the am CANNOT be used on a fixed gear/track bike.
you have to have 4 sg to back out negative torque.
the other advantage of the pro is that it is easier to calibrate (search the wattage list for details of the am vs. pro calibration).
IMHO, those two things, combined with the pro maintaining a greater resale value, makes the pro the way to go…
of course it is like crack and you end up like me with a pro, a science fsa and a 8sg mtb srm…
g
go with the Pro…hands down.
you dont have to go D/A or FSA, but at least the Pro.
Let me know if you need a deal…
KP
skip the AM… go pro… the two guys above me really know there stuff. 
This coming btw from a 4 unit power tap owner… and still happy with them.