I personally feel that Griggs is the best for roadrace applications. Sure there are others, that are great for drage racing, and street use.
Griggs does a LOT of tech support for their customers, and pay their engineers to design new equipment. Not just have someone like Granitelli rip off their design and have it mass-produced by some welding monkeys.
My GRIGGS unit going in:
http://members.mustangworks.com/drudis/mustang/griggs/
------------------
Darius Rudis
Roadracer: Home built t-arm/panhard suspension powered by an S-trimmed motor :-)
My Mustang Page