Most of the thermals I've been wearing this winter are merino, light, odour resistant, warm, wick well but I've had real issues with durability (just putting them on seems to tear them!).
The Ether Crew has done some rock climbing at Gogarth, Hollyhead and on A55 sport crags, mountain biking in Applecross and Glen Affric and more climbing in Ardnamurchan and at Reiff.
On the cool windy days cragging near the sea each day its started buried beneath a primaloft filled jacket but by the early afternoon with the sun out its been worn alone or with a thin t-shirt on top.
On the higher activity days mountain biking its been worn alone under an Arc'teryx Alpha Active Shell jacket.
So is it any different to any other thermal? Well it compares favourably to merino tops so far. Lightweight, smooth as silk to wear (flat seams aren't felt at all under a hipbelt or shoulder straps) wicks very well (I don't seem to get a clammy back in this one) and very fast drying. I haven't worn it several days on the trot yet which will be an acid test when it comes to odour retention. It also shows absolutely no signs of wear- unusual in items of my wardrobe which get used and abused!
One other 'like' about it so far is the fact that both the neck and the wrists seem to be quite resilient when it comes to stretching. I frequently like to push sleeves up my forearms and often this means that wrist cuffs stretch and become baggy. Likewise I find that neck lines soon overstretch and loose their shape but no such problem with the Ether.
As usual you get what you pay for with Arc'teryx, they put the time and money in to design and research it means you end up with a product that is reliably of good quality.
The Arc'teryx Ether Crew LS in forest green
On the gabbro on Ardnamurhcan
Sweltering on the quartzite of Holyhead Mountain
On the sandstone of sunny Reiff