Hi! To begin with, I just feel it necessary to strongly congratulate you for your fine program and to thank the developer/s for making it available for everyone at no charge.
Having said this, there's one feature of the program I have always found pretty annoying, though. I've always wondered why on earth, whenever I want the program to rename the mp3's files of a directory after the "Artist" field (using the program's "Labels-Archive name" command), instead of just doing that (as it is supposed to do on the first place, and I take it as a matter of commonsense it should do so...), what the program always does is something different. Instead of renaming files after the "Artist" field, as should be expected, what the program does is, invariably, to rename the files after whatever is featured on the "Interpreter"/"Performer" field, which is another, different field from the "Artist" field (and there are many good reasons for it to be a different,separate info field; it is obvious that the featured artist of an album need not be identic with the interpreter/s involved in performing the music enregistred on it...).
Now, this is not only rather upsetting, but it also usually leads to failure in renaming operation, multiple error messages, and it eventually may risk ending up with file corruption due to misname. The reasons for this are evident, considering that, particularly when classical music CD's are involved - i.e., with recordings of operas, vocal+orchestra, or large ensemble works-, the "Interpreter"/"Performer" field may contain extremely lengthy and complex strings of characters (to include infos about the conductor, the orchestra and the chorus, the main singers and instrumental soloists featured on the recording, etc.), all of which are necessary and useful to be featured in an info field, but will work terribly bad as a file name. Whereas on the "Artist" label one usually expects to find something quite a bit shorter and simpler, thus working much better as potential file name which is informative about the file's contents as well as short and syntactically correct too, so it won't drive mad the PC's operating system.
It would be so nice if MP3tag's developers would fix this annoying program behaviour... just please keep on making it so excellent, and congratulations once again!