Your first consideration should be proper fit. Most people wear a helmet that is too big. Some because it is easier to get on and off, some because a larger size keeps the wrong shape helmet from putting pressure in the wrong place, and some because they don't know what a properly fitting helmet feels like. The first thing to do is to measure your head, then try the helmet that is recommended for that size. I recommend removing the cheek pads at first (if possible) to get the feel for the fit on the head. The helmet should fit snugly all around, with even pressure all over. If it has a tight spot, or makes a red mark, it is the wrong helmet. That usually means it is time to switch brands or models, not sizes. Install the cheek pads and fasten the helmet. Cheek pads on some helmets can be exchanged for another size if they are too tight or too loose. Check to see that it can't be "tipped" off, and if it moves your skin moves. The helmet should not be able to swivel on your head. Wear the fastened helmet around the store for 15-30 minutes. Don't worry about how it looks, just how it feels. If any pressure points or hot spots develop, you need a different helmet. Different helmets are different shapes, and Arai makes models in a variety of shapes if need be. A helmet that fits can save your life, while a poor fitting helmet can actually endanger you. Worry about the fit first, and the style, color, venting, and other features secondarily.