After reading the description and seeing that it said, "for true three-season cycling versatility", I was immediately hooked. I have been using my Pearl Izumi shorts, but wanted a little more coverage from the sun (damn farmer tan). I am someone who doesn't mind being hot and sweaty during my ride/workouts, but at the same time, I wasn't going to buy tights with a "thermal" lining with summer coming up.
I definitely took a gamble on the sizing as I am 6'1" 195lbs and have a 32-33 waist with a chest size of about 42-44". I carry most of my weight in my legs and butt, so I chose a Large, and it fit perfectly. If you are like me and have a tall, slender yet muscular build, I would suggest the Large.