@bnemec I use seadmin to edit options.xml but I've never heard of these editors (gedit and kate). What do you see as their advantages over notepad or, if you know it, notepad++?
as mentioned by @bshand I also see the SEadmin as the more user friendly tool than any other XML editors.
But to complete the list of editors: don't forget the XML Notepad from Microsoft.
This at least is a tool especially made for XML editing
I would not advise editing the XML directly using a generic editor. I've seen some applications crash because of missing tag elements due to accidental deletion or not understanding the XML formatting rules.
If you must use a generic editor, I would suggest using one that has XML syntax checking that will warn you when it is malformed.