how is the sizing on this jacket? Does anybody know if it fits more like the synchilla which runs large or like the better sweater pullover which runs a little smaller?

It runs a little bit smaller. It's something that fits great once its on you but for convenience of layering its better to have it a bit bigger. You want to be able to pull it on and off on a whim, go bigger rather than smaller.

I agree with kris. It's short in length, as in regular-fit tee-shirt short. The width seems perfect for one or maybe two light layers underneath, while being able to layer over top with another insulator or a shell. I'm 5'10 185 and i fit a medium.

Bmac, its a unique fit in my opinion. its short in length (so it fits well under a shell), but not to terribly then that you wont fit anything under it. it has a nice tapered fit. i am 5'10 170 and a medium fits just snug enough. has a little room but not puffy by any means. i have a better sweater and i would say in with (around the chest and stomach) it is very similar, though the better sweater is longer booth in the sleeves and in the torso. the arms are also slightly roomier in the puff to accommodate layers under it.