XFCE offers plenty of settings, and even things like theming XFWM is a simple task (it's just a handful of images.) Many possible permutations of window colors, borders, fonts, etc.
Xfce works very much like the classic Gnome & Windows desktops, taskbars (panels) and desktop icons, letting you get your work done without being frustrated. Xfce embodies the traditional UNIX philosophy of modularity and re-usability. It consists of a number of components that provide the fu...
The default theme that comes with XFCE looks like something you would expect to find on Windows 98. Many PC users do not possess the necessary skills to configure XFCE in a way to look more modern.
XFCE tends to be extremely slow in it's development. The last release was Xfce 4.12 on Febuary 28, 2015, a little over a year ago, with the next release still remaining unknown.
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.
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.
Since it's basically a fork of Gnome 2, and it's created to satisfy Gnome 'purists' it's very unlikely for it to add new features more in line with modern DEs. But It doesn't mean that it doesn't/won't support modern apps.
With a focus on being "light-weight", it is to KDE Plasma what XFCE is to GNOME: a familiar enough looking lighter alternative to the more fully featured environment that may work better on lower-end devices and for people who want as lean a system as possible.
Under certain conditions, most of KDE's components can be highly sensitive to race conditions, which leads to KDE applications frequently crashing, and, on rare occasion, kdeinit itself locking up.
GNOME 3 has been designed to make it simple and easy to use. Press a button to view your open windows, launch applications or check if you have new messages.
It runs for weeks on end without noticeably increasing its memory footprint. It continues running smoothly over extended periods of time. Applications that used to crash in gnome-shell (skype-for-linux, wire, firefox) give me absolutely no problems here.