As far as I know there is only one editor... Actually it is a savegame editor, but it is limited only to characters. How 2 use it? it's pretty simple: download latest version (now it's 1.7), this is important because I could't use previous ones, they were bugged more than Arcanum itself , run it, click file, open, browse to your savegame (sometimes numbers don't match - I mean my first save is save nr3 not 1), when it loads a window will pop-up, type in name of your character (the longer-the better, sometimes it doesn't find shorter names), and edit... don't forget to save it afterall, of course... And know that cheating takes lots of pleasure from you
I do not think that the editor was bugged more then Arcanum is. After all there was maybe only one major bug in the past versions and each was fixed for the new version. Of these bugs only the major one in version 1.5 made the editor basicly useless to some.
WHere is this mysterious "savegame editor" you speak of? Is it anything like the gloriously simple falche2 for Fallout?