I just bought a couple Definity's to match a pair of older Futura's on a service van. The new tires are identical in every way to the old ones except for the name molded into the sidewall.
DOT tire code states both Definity and Futura tires are made by Cooper.
As for what they compare to, well, everyone wants to be compared directly to the global market leader, don't they? Personally I compare Cooper to Kelly-Springfield, Kumho, Hankook, etc.