Nuclear Reprocessing: How efficent is it?

I was just reading up on the reprocessing of spent nuclear fule. For anyone not familiar with reprocessing, it is a process by which the spent fuel rods from a nuclear reactor are taken apart to allow unususe uranium and plutonium as well as other radioisotopes to be recoved for the old fuel rods and used in the making of new ones. I've heard vaious things on the efficiency of the process, none of which I feel confident quoting here.

How effiecent is this process?

Is the recovered fuel worth the costs?

Anyone who could tell me something about the process, please share what you know!

Tim