I looked at a MIPS helmet at Target today. There was a piece of thin clear plastic, with some kind of elastomer between the plastic and the rest of the helmet.
My impressions were: Will this interfere with ventilation? How long will it last? How will it hold up at -20 degrees F, where many plastics become brittle? Also, the men's MIPS helmet was black, and I think that all things considered, I'd go for more visibility than for the touted benefits of MIPS.
Also, I have hair between my head and the helmet. Won't that provide the same benefit as MIPS?
I'd be all in for technologies that result in a evidence based safety improvement for cyclists, that don't discourage cycling.