I have been using a is2000 for the past year for a edge recognition application to check the accuracy of a cnc material feeder.
After every feed it is verifying the edge widths in 5 locations. Press runs up to 80spm, and I'm using 10 edge finders and 5 calculators. evaluation time is around 50ms as I recall.
For being a low end camera I think its pretty damn good. My colleagues across the pond are doing it using a 7000, but because this application is a 2 wide pattern, I was able to use one model and have it rotate 180deg.
Cognex stuff is pretty easy to use.