I used a natural for my spare ball, and as a trouble pattern strike ball for 3 years. Recently replaced it with the new blue hammer, and like it even better. Urethane is not a cure all for tough conditions, and is VERY condition specific. You have to understand that it is not as simple as finding a ball that doesn't hook too much. Urethane will still hook, but will stop hitting very quickly if you have to hook it too much. Urethane is only valuable if it allows you to play direct on a hooking condition. As a low rev end over end guy I often use it on broken down or very wet dry house shots where I can tighten my line down and play between 6 and 9 board. I will also use it on very short patterns, but I have to be careful because if the heads are flooded carrydown can be tricky.