Recs.
Updated
Xfce is a low resource user friendly desktop environment created for UNIX-like operating systems.
SpecsUpdate
Pros
Pro A true UNIX Desktop Environment
Xfce adheres to the UNIX philosophy, which means it strives for being modular, minimal and expandable. This makes it very much customizable. You can make it as minimal as you want and as heavyweight as you want depending on the features and modules/plugins you use.
Cons
Con Missing some basic functionality for a desktop environment
Xfce is missing essential functionality like a file-archiver or a polkit-client, so you have to find alternatives for those applications (eg: by stealing them from MATE or GNOME, however, this adds additional dependencies that will bloat Xfce).
Con Screen tearing issues
The built-in compositor for Xfce does not handle VSync, meaning that it does not address screen tearing for those with Intel integrated graphics. A third party solution will have to be used for those that do want VSync such as using Nvidia proprietary drivers to handle VSync or installing a third party compositor such as Compton.