NSIS is ridiculously small and for the most part very powerful. One major flaw is having to manually add a line in the script for every single last bloody file you wish to remove during uninstall. There's no way, afaik, to remove an entire folder or better yet, for it to automatically remove all the files that were added with some sort of flag. It's an annoying oversight when your program has over hundred files. You can of course write a script in PHP or C or something that generates the NSIS uninstall data. Otherwise I love NSIS and highly recommend using it. Ever since they switched to the modern GUI there's no longer any aesthetic reason to not use it. Note I've never used Inno so I have no idea how it compares.