I have a tachyon anorak here in Japan the last few months over winter. I live on the sea of Japan coast, which is really windy and wet, and gets plenty of snow. It just about never stops blowing wind. The tachyon is outstanding. I probably run hot when awake (and cold asleep) and I sweat a lot, but I have no problems chucking this on when I need it. It breaths amazingly well. I've done climbs here and in China and Korea recently where its been between 10C and -10C, and I've been powering up on foot. Strip down to basically just a t-shirt, maybe also a light beanie and gloves. By the time I get to the top, I'm a bit sweaty. Hit the wind at the top of the ridge, blowing a gale, crazy wind chill. Whip the tachyon straight out of hip pocket (it literally only takes up the size of a chicken egg), throw it straight on over the top of everything leaving on the wet t-shirt, and I'm instantly fine. It stops all the wind. It fits perfectly. The hood is fantastic. And before I know it, despite trekking down or along a ridge top, I'm dry inside. It dries so quickly, that when I get home to Aus, I'm going to try it out walking in the rain there when I get the chance. It sheds snow and light rain piece of cake. Heavy rain no doubt it will soak through, but I bet if it isn't too cold, and I'm moving hard enough, it will probably end up being more comfortable than if I had a good WPB on, at least I won't sweat it out as much, and it will dry far, far faster.
It is plenty durable to use all the time. See John Abela's review of the Tachyon jacket and Montbell Dynamo windpants. He's put their stuff through the wringer.