Greatdane,
I can not speak for the Extreme, but I have a new Liberty. I looked at the Pat, and Liberty. The Liberty was just soooo smooth! It's by far the best bow I have ever owned. I'm not a speed freak, so an IBO of 300-308 was plenty for what I want to do with it (deer hunt). If you shoot 3D as well, the extra fps would come in handy. You may want to try posting this in the Technical forum. You may get a better response there. Good Luck!