I bought this for my teenage daughter. Unfortunately the sides just below the straps stretched after just a few wears and these now stick out instead of sitting flush with the skin.
This has quickly become one of my favourite sports bras. It's highly compressive (nothing is going anywhere!) but once it's on, I don't feel like I'm wearing a firm sports bra. The fabric (which feels a little like a cross between bathers and wetsuit material to me) sits smoothly on the skin and provides no irritation under the arms at all. An absolute go to in my sports bra repertoire!