I just installed BRU - very nice. Lots of easy options there.
Love it too. I just renamed a bunch of files today, using BRU and Flash Renamer, and realized that I love the fact that BRU's live preview shows the changes in a different color. Very convenient, easier on the eyes and brain... You can also apply several changes at once, very convenient too.
But Flash Renamer (my other favorite) has some definite pluses : a "path/address bar", which is more convenient (IMHO) than the "jump to path" action in BRU; a "free select" (drag and drop) window to drop files (very convenient if you want to rename files from different folders simultaneously); a preset manager to save presets (you can save presets in BRU too, but it's not as intuitive); and other little sweet features (like MP3 renaming based on file content, file attribute changer, add different file attributes to the name, append multiple different file characteristics to the name, etc.)
Both are very complementary.