When comparing herbstluftwm vs IceWM, the Slant community recommends IceWM for most people. In the question“What are the best window managers for Linux?” IceWM is ranked 15th while herbstluftwm is ranked 19th. The most important reason people chose IceWM is:
IceWM is small and extremely fast.
Specs
Question Ranking
Pros
Pro Can be reconfigured from the command line while it's still running
Configuration of herbstluftwm can be done live in the command line, so no booting in and out of the desktop is necessary.
Pro Offers a combination of manual and automatic tiling
Users can set up auto-tiling per app, or they can change any application to manual tiling to where they want on the screen.
Pro Uses a simple bash script for configuration
The configuration file for herbstluftwm is a bash script and is easily configurable.
Pro Highly customizable
Different layouts can be used in different frames on the same workspace, so the user can customize their layout to their liking on the fly.
Pro Great multi-monitor support
Herbstluftwm has built-in multi-monitor support that can customize to any size desired on the screen. This implies that the user is not held back by being forced to use each monitor's size.
Pro Very good performance
IceWM is small and extremely fast.
Pro Excellent documentation
Since 1.4.2 and later docs are extensive and up-to-date.
Pro Keyboard operatable
Many keyboard shortcuts exist. More can be added.
Pro Very configurable
A great many options to configure it. Though this is not required.
Pro Beautiful themes available
There are plenty of pre-built beautiful themes available.
Pro Multi-monitor fully supported
Supports both XRandR and Xinerama for multiple monitors.
Pro Very Lightweight, configurable, can use as little as 4 mb of memory for window manager and tray with 4 desktops and menus with icons
Cons
Con No single window floating
The user cannot use floating for dialogs or anything else without making the entire workspace float. Their only choice is pseudo tiling.
Con No system tray
There is no system tray support in herbstluftwm. In that case, users who wish to have one must use an external application.
Con Very bad for design
Not recommended if you like beautiful windows.