Really comfortable. Wore it with just a gilet on Sunday. Warm even when its wet in the rain and doesn't stink after five hours of hard effort. Far nicer than a polyester garment and well worth the extra money.
I bought a large, but sizing is generous and despite carrying a bit of blubber at the moment I could probably have got away with a medium
On One are doing a deal on their Merino wool base layers at £19.99 at the moment. I have one of these and it's the best bit of bike clothing I've ever owned. Warm when wet and doesn't stink like polypropylene.