Chris Daviswrote a review of Smith Vantage MIPS Helmet on January 25, 2017
Familiarity: I've put it through the wringer
I'll spare you all the details of the accident but I've taken my fair share of falls on other helmets and I'm convinced that the way that MIPS helmets dissipate the force of a fall left me with just a mild concussion when it could have been exponentially worse.
I'm trying to avoid hyperbole here because saying things like "saved my life," and "could have been exponentially worse" are certainly not quantifiable in this instance, but I was going hella fast and fell a hella long way and I'm here a day later with only a mild concussion and couldn't be happier about that result.
I'm not saying you should buy this particular helmet, but I do think that the concept of an inner lining (and your brain) moving independently of the shell is a smart innovation and worth adopting.