Better Rename 9 is buggy. It would be most useful for large numbers of files, but thats exactly where it falls down. If you feed it too many files at once, it will get stuck in a loop where it tries to count up the items to rename, but just keeps counting to infinity. You are stuck waiting. Worse, the "OK" number of files varies wildly. Sometimes upwards of 10k are fine, sometimes it has to be lower. You cant tell if it is going to fail until it counts all the way up. Ive hit this bug across multiple OS versions, multiple computers, and multiple Better Rename versions. The bug has been around since version 8 at least, and remains unresolved, despite the fact that it has been reported and that it has a major impact on the usability of the program. The presence of a giant, obvious bug like this for so long shakes my confidence that this program is actually renaming everything correctly. Additionally, the interface for saving/reloading rename operations is clumsy and awkward. Overall, I gave it a 2. It works to rename files, at least sometimes, but it is frustrating and difficult to use due to a poor design and bugs.