In my experience, there's nothing like DiskWarrior for repairing a damaged disk. It's like a fire extinguisher, you may never need it but when you do, you'd pay almost anything to have it next to you.
The new version ships on a USB disk (finally) and is also updated for the latest OS. Interestingly, it will also now repair TimeMachine disks.
DiskWarrior is a professional tool (I've seen it used at the Genius Bar many times) and the price reflects that. Just the upgrade is $60. It's market pricing by my estimation since there's not much that can compete with it when you're in a pickle.
By way of MacInTouch