The material is not itchy (it's soft and pleasant against the skin). It is comfortable, substantial, doesn't wrinkle badly, and is natural and breathable.
It's very quick to hand wash -- I mean, like 3 minutes. The label says it's machine washable, in which case a mesh bag in a cold-water delicate cycle would be in order.
As for sizing: I'm 5'4”, 170-ish lbs, and Large is the right size for me here.
Each one of us is different, of course, but I was worried that, as a woman in my sixties and no skinny Minnie, this might look silly or boxy on me. But, my 24-year-old, beautifully stylish niece, who would not hesitate to be candid with me, gave an enthusiastic thumbs up and encouraged me to get the other colors. Actually, I've been surprised to receive quite a few compliments.
Anyway, I'm obviously making good use of these purchases, but if they'd only been good as pyjamas, I'd have enjoyed them as well.