This Marmot top is made of a silky smooth fabric that is really nice, but there are a lot of flat-locked seams on this garment, and the thread is pretty scratchy. I notice it most in the sleeves. Also, the sizing is pretty darn small. I generally wear an XS or a S. Since this is a base layer piece, I opted for the XS (also, I don't think size S was even available). It's pretty darn snug, especially in the shoulders (I'm no burly swimmer, but I don't have super small shoulders, either). I think if I sized up, the top would be fine, and the scratchy thread wouldn't be as much of an issue, either, since it would not be rubbing against my arms as much.