Although we had quite a few problems with tread breakage in 2004, our first year attempting a tank tread design using Brecoflex belts, we've had a lot more luck with Brecoflex in 2006-2007. We broke one tread in 2006 due to overtensioning by an exuberant student. We had a few tears in 2007 and a tendency for our tread modules to wear away the edges of belts (didn't affect performance), but nothing that could be characterized as a chronic problem. We've used a swappable tread module design in both years which saves us downtime in the event of a jam or break.
Our experience has been that our tank-tread robots have excellent straight ahead pushing force, but we haven't solved the smooth zero-radius turning design challenge many tank tread drivetrain designers face. Proper robot weight distribution and setting the correct "bogey" wheel depression are crucial to smooth zero-radius turning. In addition, the relatively heavy weight of a tank tread drivetrain sucks away weight budget which could be allocated elsewhere.
I agree that the red linatex backing is a very robust and hardy belt material regardless of the tread supplier. I prefer it to Brecoflex's Supergrip Blue and Green.
Team 379, the Girard Robocats, used the same set of red linatex treads THE ENTIRE SEASON last year, and I believe they were Brecoflex. The treads were still in great shape after 3 regionals, Atlanta, and Kettering. They also had better maneuverability than we did. I'm sure those guys would have some advice for you.
I've asked Mike Mellott, our lead mechanical designer, to post more detailed information on our Brecoflex experiences.
Here's a pic of the side view of our 2007 robot. It doesn't show much but gives you the general idea of our design:
http://www.chiefdelphi.com/media/photos/27491
FYI, we're currently experimenting with various "half-track" module designs which use much shorter (and therefore cheaper) belts. We ran with these at IRI and Kettering Kickoff with much success and much improved maneuverability, at the expense of pushing oomph. They were also much, much lighter than our full-length tread modules.
Finally, we have no experience with the Gates belts, but there's no reason not to trust the endorsements of the others who have advocated their products in this thread.