DesktopServer is the easiest way I have found to efficiently develop WordPress sites. I use the limited version, which allows the installation of three WordPress websites. This is enough for my purposes since I use it mainly for theme exploration and the early stages of development.
I find it particularly helpful in developing child themes. Everything is right there on my local computer so I don’t have to download parent theme files and upload them to the child theme. Two of the three installs are currently dedicated to websites I have in progress. The third install is being used for broader testing, and is especially useful in theme selection. Having a dedicated testing site for themes allows me to explore multiple themes before committing to any one theme for a particular site. I find it helpful to import any available theme demos to learn how the theme really works. After deciding on a theme for a specific site, I install the selected theme to the designated test site, without the need to import the demo.
I use DesktopServer to develop WordPress websites before launching them publicly, but have also found it to be a helpful tool in expanding my learning of how WordPress works.