Sun shirts...

I have 3 that I use:
Ariat- by far my favourite. I find it very cooling, nice shape/fit and washes well. Good tailoring. XS fits perfect, but the S looks ok even if too large because it is cut well.

Bette and Court- Odd sizing. Small is huge on me and looks odd, but XS clingy in the bra strap area. Not flattering. Ok for cooling. Washes up wrinkly. Was the most expensive of the 3.

Greenhawk brand (Aerion)- Worst the bunch but also way cheaper. Washes up well, has mesh panels but the fabric is smooth nylon type that doesn’t seem to breathe as well. Boxy fit, fits large for XS but doesn’t give me the funky tight bra strap area. For the price, they are ok but if you can get the Ariat I’d go for that. Zipper is rough, cheap quality but it works.