William M.wrote a review of Arc'teryx Gamma MX Softshell Jacket - Men's on October 23, 2013
I bought this to replace my 2nd Gamma MX since I got a screaming deal. I am sold on the concept of this jacket and use it as a light shoulder season jacket on it's own and a layering or high exertion piece in the winter. I rarely use sweaters, fleeces anymore since buying the MX. Between a short sleeve or long sleeve base layer, the MX, and a shell in various combinations I'm set for 85%+ of the conditions in CO. I swap out the MX for an insulating layer only when it really gets really cold.
That said - I don't like the new Fortius material nearly as much as the old. The face isn't as slippery (read harder to use for layering) and it feels warmer, but not in a good way. Where it used to be a perfect for 35-60F depending on level of activity, it now feels too warm at the higher half even as a casual piece.
I also don't like that they relaxed the fit of the XL. Now too roomy in the arms and gut even for a big guy. It is much less athletic. I'm a big fan of Arc for not assuming that all XL guys are fat arses like NF does, but they headed in that direction in this version of the Gamma MX.
Long and short is that I sent this back and will ride out my current MX until it is really threadbare.