What do you like best?
XFCE's best features include portability and completeness.
XFCE is very easy to use for most end users. When looking for a quality desktop experience, most users utilize Ubuntu, but when using other Linux operating systems it is convenient to have an option to easily install a desktop that is easy to use. XFCE will run on anything that handles X11 which gives it almost complete support of all Linux Operating Systems.
XFCE has everything expected of a base desktop environment. It boasts a full office suite along with basic utilities such as paint, email, music, and web browsing programs. All of the programs boast robust open source communities, and are great quality for a free desktop environment.
What do you dislike?
Size. XFCE will run on a variety of hardware, but it is far too heavy weight for embedded systems and microcontrollers.
Customizability: despite a robust theming engine, if you choose to utilize another program to replace something in the suite, you still cannot remove the unused suite program without uninstalling all of XFCE.
Recommendations to others considering the product
Try it on a live USB before implementing it in your workflow.
If you are looking for a lighter experience, consider using a window manager like I3 with raw X11.
What business problems are you solving with the product? What benefits have you realized?
XFCE is spectacular for:
using as a default desktop environment in a live USB for testing computer hardware
Open source fans looking for a free full featured desktop environment
Those looking for an alternative to the Ubuntu Unity desktop
Those looking for an X11 based desktop environment