In my early years of backpacking my standard piece of summer head wear was the simple, but versatile bandanna.
It would keep the sweat out of my eyes (no easy task), as well as serving as a pot holder, wash cloth, water strainer, etc. Few pieces of gear can rival it's multi tasking capabilities. The bandanna still has a place in my kit, but I think it has finally been ousted by the Supervisor by Headsweats.
I've never been much of a visor kind of guy, prefering baseball caps for my ever thinning hair (I don't have a forehead, but a five head, if you will). Even so, I decided to give the Supervisor a try. After using the Supervisor on my last outing to the Adirondacks I'm here to say my trusty old bandanna has one less task to perform.
Being a heavy sweater I appreciated the open air feel of the visor. It fit well and felt quite natural. The Cool Max terry liner worked so well, not one drop of sweat rolled down my face during the entire trip. In fact, if I tilted my head down the sweat would drip off the tip of the brim, but never on me. Speaking of the brim, keeping the sun out of my eyes was greatly appreciated and would never have happened with a bandanna.
I'm sold on the Headsweats Supervisor, and highly recommend it for your warm season hikes.