Compelled to write a review after a season, this is the best shell I have used to date. Used this for ski mountaineering in all types of weather - winter through spring. I was looking for a way to cut a layer out of my pack. I used to carry an insulating outer jacket, softshell and hardshell. Had heard Neo Shell was super breathable and gave it a try. I don't pack my softshell now and haven't looked back. This will keep the rain or snow out, it's fully waterproof so works as my hardshell. It does breath very well (so much so that you will feel some draft from a strong cold wind through it - similar to Polartech Power Shield). I've even worn this skinning up a slope and been very comfortable which surprised me (as I used to strip off to bare bones to avoid sweating). Fit is athletic, I'm 5'11 190 and large fits great. Has held up well and looks almost new so far. I'm an Arcteryx fan, but this RAB is a keeper, definitely would buy again if i lost it. Highly recommend.
I had the old version of the G'Mx (3yrs old), it was a work horse. Decided to update the gear and I now have the new one now. Noticeably better constructed than the last one. The fleece is more pill resistant and seams in the hood and inside the jacket look more finished. I had a couple of ski tours in mine and I think they're pretty comparable. Fit seems similar, I'm 195 6'0 and found the medium a bit tight around the waist (36") - top fitted great though. Went for the Large and can fit a heavy base layer plus something like an R1 if needed without feeling constricted. This isn't windproof (thankfully) - breathes like a champ. I throw on a shell for the down if needed. DWR works well. This one does seem to pick up a funk quicker than the old version - little aromatic, nothing really offensive like the old capeline but noticeable (which annoys me, I have the Accelero for running in and that never ever smells, they need to add something to this jacket for the money IMO). Fits a specific niche for high output / cold days where you need to be free to move. Gets four stars based on price.
Owned for one season so far - great fit, I'm 185 6' and large is perfect. Used for running in cold weather (below or close freezing) and mountain biking. Holds off rain / snow for short showers. Also used for ski touring while skinning - worked great. I have the Epsilon AR as well. For comparison this is a thinner material which has taken some serious abuse with scrapes passing trees mountain biking and still looks new but might not be as burly as the Epsilon - it also feels like a closer weave and so keeps a little more wind out than the Epsilon but still really breathable - (bonus is it doesn't stink either after months of use). Very happy with it. About to buy a 2nd one.