Tatum is better but the gap is not as wide as some will try to make it seem. Brown is a legit 20 ppg scorer who defends too and is getting better every season on both ends. His ceiling isn't quite as high as Tatum's but he's a damn good player who possibly can be the second best player on a title winning team. And i think he would be even better if he actually played small forward the majority of the time as well which may become an issue eventually with him and Tatum on the same team. But the Celts have made it work this long so i wouldn't dare dream about breaking them up anytime soon.