Jerimoth wrote a review of Mammut Felsturm Half-Zip Jacket - Men's on July 17, 2012
The jacket is stunning in appearance, and although I did not wear it outside I have another GT active shell garment and I can say that it definitely breathes better than Pro Shell. The helmet issue is a problem, but for me the half-zip is a more serious problem. Of course I knew it when I purchased it, but half-zip jackets for full-on mountaineering do present problems in terms of taking them on and off, but more importantly, they do not vent as well as full zips. It is a very well constructed jacket, and if you are not using a hood, and are comfortable with a half-zip, then this is otherwise an excellent product.