I'm usually a small or xs - ordered the small and glad I did.  I think the xs would have been more form-fitting, but the fabric is not too stretchy and would restrict movement.  The fabric is also very shiney, silky, and soft, but not matte or sueded - not sure why it's called "peach skins".

Pros:
  - Good proportions - sleeves, body length, chest, and shoulders.
  - Feels nice to the touch.

Cons:
  - The neck opening is reeeeeeeeeally small. It feels fine after it was on, and maybe it's a small opening to keep you warm, but it barely stretches at all to fit over your head, so it messes up your hair and makeup.
  - Not too much stretch in the cuffs of the sleeves, either.
  - Wore it for outside activities and didn't think it was THAT warm - when the temp dropped below 57, I needed a jacket.
  - Not that thin