The primary difference between Pathfinder and 5E is the difference between optimized and non-optimized characters. While there are a few things that can be done to min-max your character in 5E, regular characters don't lag very far behind, making min-maxing less efficient than Pathfinder. This means that character creation and leveling don't have to take nearly as long to do, but players who like system mastery benefits sometimes find it lacking.
Something else to consider, is that Pathfinder is about to release a second edition. If you can, you are probably better off waiting for that to be released, rather than trying to get all the books for the first edition system.