In reply to Robert Durran:
The thing is designed by and for Uli Steck. His climbing is characterized by continual aerobic motion (often, because of his astonishing speed, for no more than a few hours even on huge objectives). He isn't going to stop to take it on and off, because...he isn't going to stop for anything. So if you want a super light waterproof piece you put on first thing and wear all day, this could be it.
There's a more useful review of the original jacket (which didn't have stretch panels) on the Supertopo site,
http://www.outdoorgearlab.com/Hardshell-Jacket-Reviews/Mountain-Hardwear-Qu... . They compared it to 18 other hardshells. They found it to be the most breathable, which fits with Uli's style. They also noted that breathability came at the expense of windproofness, which would matter to those who stop to belay more than those who don't. They liked the seal of the cuffs but didn't appreciate the feeling of having "wet socks" around their wrists in wet conditions and weren't happy about having to remove gloves to remove the shell (which of course Uli wouldn't be doing). It was their testers' first choice "for all things wet and cold," but for those who aren't professional athletes able to re-supply whenever needed, they also found it to be "shockingly fragile."