xterm vs Terminology
When comparing xterm vs Terminology, the Slant community recommends Terminology for most people. In the question“What are the best terminal emulators for UNIX-like systems?” Terminology is ranked 9th while xterm is ranked 13th. The most important reason people chose Terminology is:
Font size in Terminology automatically scales according to window size. When you resize the window, so does the text.
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Pros
Pro Lightweight
Xterm is a very lightweight terminal. It requires few resources, allowing it to run well even on lower-end machines.
Pro Used in almost every Linux distribution
If you master xterm, you won't have to learn another tty, since it is in almost every Linux distribution.
Pro Stable, well-tested
Pro Standard with X Window system
Xterm is installed as standard software with the X Window system, and is there even when installing other terminal emulators.
Pro Supports sixel images
Pro Shows full characters for wide fallback fonts
Many terminal emulators that deal with wider fallback fonts (i.e. double-wide characters in CJK fonts) truncate display of wide characters, show Unicode "missing glyph" characters, or simply fail to display the characters at all. XTerm is "smart" enough to simply take up the extra space needed to show such wide characters.
Pro In about 30 years, it had only one issue, and that was fixed quickly
Pro It is fast and responsive
See this.
Pro Many modern terminals emulate xterm
Many terminal applications, such as OS X's Terminal.app and iTerm2 (among others), all claim xterm or xterm- variants as their $TERM and aim for support of xterm's escape sequences. Many command-line applications will assume or even hard-code escape-sequences and behavior for xterm and those terminals emulating it.
Pro Configurable via Xresources
X Toolkit resources and xrdb predates what is currently called "theme". Although one needs to read man, mitigates most listed cons
Pro Scalable fonts
Font size in Terminology automatically scales according to window size. When you resize the window, so does the text.
Pro Looks smashing
Terminals are often very dull looks wise, not so with terminology.
Pro In-terminal video, picture and thumbnail support
Thumbnails, pictures, and videos can all be rendered in-terminal, based on the directory listing or mouse interactions. For instance, using "ls" on a picture folder will produce a list of thumbnails instead of only the filenames.
Pro Splitable
You can split windows, like in terminator.
Pro Visually customizable
It is very customizable in every aspect of the visual options.

Pro Integrates well with Enlightenment WM
Terminology is part of the Enlightenment WM packages. As such, it integrates really well with Enlightenment and other tools in the package.
Pro Block copy
You can copy text in blocks.
Pro Copyfree licensing
Terminology uses the Simplified BSD License. As it is a copyfree license, it tends to minimize license incompatibilities, legal compliance requirements, and various other complexities that may make it difficult to understand certain licenses.
Cons
Con No native transparency
Xterm does not natively support transparency (though it can be emulated if needs be).
Con Bad defaults
Very small default size. No way to know to how to configure size.
Con No tabs
Con It blinks
If it blinks for you too, you can try this: man xterm
and then press Shift+G.
Con Has few dependencies
Has dependencies like xbitmaps.
Con Historical source code
The stories behind terminal emulation beyond their classical representatives (of which xterm is simply the most long-lived) are somewhere inbetween subtly irritating to downright surreal.
Con Configuration is sometimes complicated and non-obvious
There's a "Settings" menu for configuration, but more options there would make it easier. Downloading themes and extensions from the official repo would be a big plus.
Con No True-Color support
Not able to display a modern full range of colors, yet.
Con Scrollback is completely nroken
Scrolling back the emulator inserts random lines from other places in the scrollback buffer in between the actuall output lines. Thus it is impossible to see a correct copy of the previous output.
Con No scrollbar
The lack of scrollbar in Terminology makes navigation difficult. But you can use keys for it.
Con Too many bells and whistles
Some people feel that Terminology has too many features that are not suited for a terminal, but for a window manager instead. For instance, viewing thumbnails, watching videos and gifs, and other similarly flashy things just feel like eye candy and should not be part of a terminal emulator.
