Advanced Installer

If you need to produce a Windows installer for your software, my advice would be to forget the ancient NSIS, bypass the disappointment of WiX (yes, it's free, but it requires a lot more work for the same results in my opinion), prise open your corporate wallet and spring for Advanced Installer.

The pricing is somewhat robust, especially if you want the editions which will do things like IIS setup, but the reason they can charge that much is that it Just Works. Typically, an installer is something you'll spend a couple of weeks setting up and integrating with your continuous integration, and then you won't touch it from one year to the next after that.

This being the case, having a comprehensive UI for modifying it is much much better than faffing about writing "code" or XML which you've forgotten all the details for by the time you next touch it. To be clear, though, Advanced Installer does produce plain-text files which you can check in to version control and then feed to its command-line mode to build yourself an MSI or an EXE.