@Odin : The downside (if you’re using a standalone tiddlywiki) is that if you ever need to use your browser’s debugger, you basically can’t now, because all the javascript has been obscured, and mostly fits on one line. That’s the only downside though.
It won’t prevent you from upgrading your wiki to the next version. Upgrading would replace uglified code with pristine code, which you could uglify again. Uglify only ever touches plugins, not non-plugin tiddlers, so it’s reversible (sort of) in that you could just drag-and-drop reinstall all your plugins and undo all the effects of Uglify. If you’re using NodeJS instead of a standalone tiddlywiki, then uglify is completely reversible, since your server will do its own uglifying and send the uglified versions to the client, but all your files on the server remain untouched.
However, if you do have concerns, then I wouldn’t worry too much about it. I developed the plugin for people who have particular reason to be concerned with file sizes and network bandwidth. It won’t noticeably speed up your Tiddlywiki or anything.
@TiddlyTweeter : Also, I think technically uglify is the more correct term. It modifies javascript and json source code to be smaller, but it’s still technically uncompressed. In fact, if there was a TW5-compressor, you could apply that along with TW5-uglify and gain benefit from both.