I wanted a helmet to cover me for putting in the miles on the road and trail riding. I didn't want to go down the pathway of two different helmets, and would rather a bit more coverage and protection than the lighter, more minimalist road helmets. The Plasma is perfect for this application, and looks good doing it. Ventilation is paramount - it is regularly >100F during summer where i live and the Plasma is extremely well ventilated. I don't think i have a particularly oval or round head and it fits me the best of any helmet i have found to date. Sizing is perhaps a touch small. If in doubt, go up.