More brightness (a wider light pattern that shines well in front of even the fastest rider), better run times, connectors you can count on (no sudden outages just as you are descending), better mounts (that won't break when you crash or drop the bike), better battery setups (pulling batteries out every time you need a charge will wear out the battery holder in no time), more reliable in wet conditions, just about every aspect of the system will function better and last longer.