When comparing Mezzo vs LXDE, the Slant community recommends LXDE for most people. In the question“What are the best UNIX-like Desktop Environments for everyday users?” LXDE is ranked 5th while Mezzo is ranked 20th. The most important reason people chose LXDE is:
LXDE is a simple desktop without a lot of bells and whistles, this allows it to remain lightweight which helps conserve battery power and maintain its speed of use.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Available as .deb package
Mezzo is available as a .deb package, which makes it very easy to install it on Debian or Debian derivatives such as Ubuntu.
Pro Energy saving and extremely fast
LXDE is a simple desktop without a lot of bells and whistles, this allows it to remain lightweight which helps conserve battery power and maintain its speed of use.
Pro Simple and straightforward menus
LXDE utilizes a XP like menu which is straightforward and familiar to many users.
Pro Nicely balanced between speed, stability and features
Pro The most lightweight desktop environment
LXDE is by far the most lightweight desktop environment, even topping XFCE.
Pro You can setup LXDE with the same look across different machines easily
Most of the configuration of LXDE is read from files. Consequently, you can store and manage these files in the same way you might manage other dotfiles, meaning that you can setup LXDE to your liking on a new machine very quickly and easily.
Pro Uses Openbox
Pro Designed for cloud networks
LXDE works well on lower end devices such as cloud computers or netbooks. it is able to do this because of its low CPU and RAM requirement.
Cons
Con Possibly discontinued
There's not much new information about Mezzo around, and all the articles or forum posts about it are quite old which may be an indication that it's probably abandoned now.
Con Doesn't look very well out of the box
But it is very customizable.
Con Deprecated
Development has moved to LXQt.
Con Ugly and horrble UX
Con Development has slowed
LXDE is slowly reaching End of Life, but will still receive new updates as long as GTK +2 is in use.
Con No compositor
In order to keep the system light weight and CPU/GPU non intensive LXDE forgoes a compositing program, because of this there will be screen tearing. Though a compositor like Compton can be added for those that want it.
Con Only halfway to GTK+3
Most of Xfce's components were built in GTK+2 and the upgrade process to GTK+3 was very slow due to the lack of manpower.
Con Uses GTK
Nowadays, GTK is designed primarily for use with GNOME and with only GNOME in mind. Trying to do anything else with it results in needlessly hacky, unattractive programs.
Con Openbox doesn't support Wayland
Con Problem with log in
"The session is locked" message is a frequent problem when working with Lubuntu.