I've used 3 different REQ solutions in my A/V systems: Dirac Live, Audyssey MultEQ XT32, and ARC Genesis. I consider them all effective, to varying degrees, with respect to reducing room colorations and providing a more convincing audio experience, at least to my ear.
However, REQ is intended to remediate only room anomalies. It is not a panacea for speaker or source aberrations. And I've always found further improvements to the sound are possible via manual adjustment downstream. YMMV