I’ll start by saying that the feel and weight of these sweats are unparalleled. They are so comfortable and heavyweight and just feel expensive and nice. I have the abercrombie open hem ones, and this one is miles ahead in terms of material and quality. I believe it is well worth the $70, I would even pay $110.
I'm 5'10, 220lbs, and a 34-36 or medium in jeans/trousers. I got a small since they were sold out of the medium and I didn’t expect them to fit but I wanted to just try them out, and they literally fit well; if anything, they’re a bit too big. I have to tighten the waistband to stop them from sagging. So they do fit bigger, and I would recommend sizing down. The length is a bit too long for my liking and I will be getting them hemmed which I don’t mind since I love these sweats so much. But yeah size down.