Bought one of these at Haydays this year, yesterday was the first day of riding with it. Never having worn any type of vest before, it initially felt bulky under my monosuit, but after riding a bit forgot I even had it on. Was very comfortable, and added some warmth. I also have the 509 knee pads, those are also very comfortable to the point you don't realize you're wearing them. The shin protection on them is also a plus. One thing to note on the knee pads--they run small. I'm 6', ~200 pounds, and was right on the maximum end of the sizing chart for L/XL. They fit, but were a bit tight when putting on. Have the XXL/XXXL now, they aren't a ton bigger, but definitely easier to put on and take off.