Was in use on one OC expedition I participated, 60+ diving for 10 people every day.
Gases we mixed was something in the range 17/50 and 50% or so.
I was not involved into the mixing but my impression it worked well and fast when tuned in, AFAIR final He-content was a bit to high compared to what the display said so it was tuned down a fraction and all au point then.
Temperature was hot croatian summer, might be different when cold.
Compressors were brand new, no blow by AFAIR.
Nitrox absolute no-brainer with it I'd say, I'd still guess you need dedicated people mixing the gases with a feeling for it, so not like a membrane, not for "everyone" in the club IMHO.
HTH,
Hoffi