I've had two. The first one was the "breathable" fabric, which I ordered by mistake and didn't trust enough to use. The second one was the more waterproof version.
I wore that one as a rain jacket on a winter trip last year. In the low-40s, with the sides fully unzipped and the front unzipped down to my stomach, I was drenched with sweat after a couple of hours of relatively easy hiking in the rain. The jacket didn't wet out, but even vented just about as much as it could be, it also didn't breath at all. That might be a trade off you're willing to take, but I ended up going back to an OR Foray after that.
The Stash does pack up nice and small, and is as light as advertised. Maybe be a good option if you won't be moving in it, just didn't work out for me.