Recs.
Updated
Fluxbox is a stacking window manager for the X Window System, which started as a fork of Blackbox 0.61.1 in 2001, with the same aim to be lightweight. Fluxbox also has several features Blackbox lacks, including tabbed windows and a configurable titlebar.
SpecsUpdate
Pros
Pro It's easy to find many new styles and configuration options
Fluxbox has many great themes and config options that are ready for download and installation. In addition to this, there is great documentation on how one can make their own themes or edit their own configs to their liking.
Pro Styles (themes) are easy to manage, create, and change
Simple to style and has many styles available. You can also change styles real-time.
Cons
Con Difficult to master
It does take time to learn the ins and outs of all that can be changed by editing the configs. It can also take some time to finally attain a configuration that is perfect. Many users constantly change and edit their settings, but consider this part of the joy of using Fluxbox.