Most scripts make you upload files, CHMOD them and run complicated setup/upgrade processes. With WSN Shop, upgrading to a new release is one click in your admin panel (no uploading, no permissions issues). You can even use a tool to upgrade dozens of your sites at once. Initial setup is also super-simple: upload one file, fill in your database info and it'll install the rest of the files automatically.

If you'd rather do nothing at all, professional installation is free and one upgrade request per month is free.