Spend the extra $25-$30 now; if your head ever hits the ground, you'll be glad you did. MIPS (Multi-Directional Impact Protection System) adds a low-friction layer inside the helmet so your head can rotate slightly during an angled impact. That engineered slip helps reduce rotational stress on the brain-the kind that shows up in the real crashes most cyclists actually have. If my head ever meets asphalt again, I want MIPS between me and the ER.