There are lots of renaming utilities out there, and I can't claim to have looked at every one. But one's download link was broken, one crashed every time for me on 10.1.4, etc. etc. This one actually works, and it does a good job; took me about 30 seconds from when I double-clicked the .dmg to when I was done with the renaming task I needed to do. Brilliant. I'm not rating support, docs or features since I didn't really look at them much.