I bought the Rudy Project's Syton Supercomp helmet, which is basically the Syton with removable ear covers and a windshield. It is my first aero-helmet. I wasn't sure how much of an advantage it would give. I wore it for the olympic distance Mexico Beach race, but since it was only my second olympic, it was hard to tell. I also just wore it on Saturday for Emerald Coast #4. That's when I realized how much it helped. My bike time was only 30 seconds slower than last year...but I was in way better shape last year and last year's race didn't have the killer bi-directional headwind. That's right...the wind changed just after I turned around, so I got a headwind both directions.
Makes me feel like I'm getting my money's worth out of the Syton.