I have a 24" head and this hat in XXL fits perfectly and does not squeeze my head and give me a headache.  It's quite lightweight.  It's cool because of the netting around the circumference.  The roof of the hat is cloth.  I've worn it in 90-sun and my head stayed as cool as could be expected.  The brim protects the eyes, most of the face and the neck all around.  I'm old and bald and I've been looking for the perfect summer hat for decades.  I'll give this one a 97%.  The sweatband feels very soft and comfy.  I love that this hat doesn't squeeze my head and give me a headache.  I'm not sure the brim has to be as heavy gauge as it is; but it is still very soft and pliable, nonetheless.  Most people probably wouldn't even mention it.
My ideal hat would be one that kept me from getting a sunburn on my head and face, would make my head feel like it was 70 degrees in 95-degree sun, one weightless so that I couldn't feel it on my head and one that shaded my eyes.  This one comes pretty close.