Hi Lee,
From my experience with both I would strongly recommend modified one. I found it very difficult to find a bright star for autoguiding near many DSOs. Now it's much easier with modded ToUCam(I use ATiK version) as I can set exposure to >1/50 sec and there is always at least one star visible by GuideDog. See
this thread
P.S. May be it's just me as Doug seems to be very happy with result :-)
cheers,
Michael