I can say that I didnt have any major problems with the Jaco tires when I ran them last summer.... I cracked one wheel (a very small crack) from a MASSIVE hit that would have either warped or cracked any other wheel. So in my mind the jaco stuff was just fine for me.
The only gripe I had is the tires wore out a little fast because it was probbaly too hot outside for the blue compound. Other than that, they were awesome!
-Korey