About differences between
openbox and
fluxbox ... and
pekwm.
WINDOW SWITCHING BEHAVIOUR
Proper 'ALT-TAB' behaviour is only available on fluxbox and openbox, pekwm lacks a lot here, check this for more information:
http://pekwm.org/projects/pekwm/tasks/210
While fluxbox switches between windows instantly, openbox/pekwm can show list of windows while switching and openbox can also show black/white border for every window (like metacity).
WORKSPACE MENU
The so-called workspace menu in fluxbox expands into submenu for each workspace, which makes its useless for generall usage.
Both pekwm/openbox provide here workspace menu that shows all apps on all workspaces isntantly, but only openbox can render all application icons properly here.
PROPER ICON RENDERRING
Both pekwm/fluxbox cannot render application icons properly, while openbox can, fluxbox renders properly icons in the root menu, but only if you select exact size for the icon (same as actual image size), if image is bigger, its scaled version would be ugly.
WORKING AREA
At both openbox/pekwm we can set margins for the workspace, the space on the sides which will NOT be used for windows, to achieve the same on fluxbox, you can only use dome dockapp with displaying transparent PNG file (dirty hack) with do not maximize over slit option.
ACTIONS ON WINDOW BAR/BORDER
At pekwm/openbox we can define various actions that will happen when clicking/scrolling the window border/bar, some custom commands (like transparency increasing/decresing with transset-df), fluxbox can not offer that
STANDARDS
Both pekwm/fluxbox are NOT fully compilant with NETWM/EMWH while openbox is (but I never suffered from the fact that they arent fully compilant).
LANGUAGE (as curiosity)
Both pekwm/fluxbox are written in C++ while openbox is written in C, which make it little faster, but its propably hard to notice this on Core 2 Duo class machines these days.
OTHER
Both pekwm/fluxbox support tabs, but I do not remember when I last used them
From these two fluxbox also offers taskbar, but being frank with you, I must say that having so nice
workspace menu on openbox I do not need taskbar any more.
COMMAND SUBSHELL
If you put something like that into fluxbox root menu [cmd=]feh --bg-scale $( cat ~/.fehbg | cut -d ' ' -f 3 )[/cmd], then fluxbox will execute that without any problems, while openbox will throw an error (havent checked for pekwm), same for [cmd=]` ... `[/cmd]
... my thoughts on differences between these 3 WMs.