My take is most people write code in a write optimized manner. Foo_to_Bar is much friendlier for the writer as auto-complete will come up with all the Foo_to_Xs

My take is most people write code in a write optimized manner. Foo_to_Bar is much friendlier for the writer as auto-complete will come up with all the Foo_to_Xs you can use, whereas the Bar_from_Foo format requires the writer to know that they want to use Bar up front.