You probably will want to give doing a combination of the two for the best results.
Set up one as a pure FK, one as a spline, and a third that blends between the two. Depending on how complicated you want to get with your blending, you can get some excellent results out of that. If you have the time, setting up a blend that can happen locally or at selected joints is a great way to achieve both.
If you want to get really complicated, get all of that working in concert with a path animation ability as well, with the ability to select parts that are or aren't on the path.
It can get complicated quickly, so break it in to pieces and figure out how much time you have/how far you want to get even before you start.