Looking for an id3 tag editor

I am hoping to find a decent id3 tag editor. I don't mind using itunes to play the media, but so far I keep the actual library externally to it and import parts at a time when I want to listen to it. So even if I change the genre or whatever in itunes, its only going to last until the next time I wipe it out and import the songs again.

Im running the recent mavericks update of osx. I just tried a few, winamp seemed to crash and also not able to edit the tags. I then tried SimpleTagger and MetaX and I had trouble running both of them. I got an error saying they were from an unknown developer and I couldn't run them.

Looking for an alternative or a way to get those unknown developer apps to run..

Thanks.

I was wondering if there was a way to do it with iTunes. Thanks.

edit: got it to work!! I just wanted to rename this one group of new files. I found out you can bulk edit in iTunes by highlighting a group of files, right click and look for get info. There you can check a box and type in and it will apply it to them all. I tested it by removing them from iTunes and re-importing them and it took.. brilliant. Thank you once again.