Any mill with close to the same HP is going to go though the wood close to the same speed, a good operator who can make up his mind in a second will speed up production the most. You for sure want a chain turner on any portable mill. For sure look at Cooks and Baker also but I think Baker runs sandwich type guides which I've never used but I like roller guides with down pressure better. Also maintenance will be a big factor in production, a mill broke down is costing money not making money . Steve