Yup...it's fully proprietary... so MA has exclusive rights...I'd still put my money on the RAAL but of course how its all implemented is key to any & all speaker designs. I suspect those MA gx300 would sound awesome.
Old Indian proverb: We don't inherit the earth from our ancestors, but we borrow it from our children!
Ascend Acoustics Towers, STC w RAAL, 200 SE in espresso
54" of Panasonic Bliss, Anthem MRX 300 Sony BDP-S380, TechnicsCD player, Apple TV PSA XS30 SE in Cordovan Cherry & Svs SB13U in sig
I've auditioned most of the speakers you listed. I haven't heard the Monitor GX300, and the Sierra Towers I heard had the NrT tweeters in them, but if I were choosing for myself off the list you gave, I'd go with the R900's. They had the smoothest. most natural sound of the speakers you listed that I listened too, a healthy amount of bass capability, and great imaging.
Just my .02
Augustine's Law: "The last 10% of performance generates one-third of the cost and two-thirds of the problems."
"If it works the first time, it's not high end." ~ Harry Pierson