When comparing rxvt-unicode vs Termite, the Slant community recommends rxvt-unicode for most people. In the question“What are the best Linux terminal emulators?” rxvt-unicode is ranked 4th while Termite is ranked 9th. The most important reason people chose rxvt-unicode is:
Rxvt-unicode uses very little memory and takes a lightweight approach without losing many important functionalities. A single instance of urxvt takes about 6.5MB-8MB of RAM.
Question Ranking
Pros
Pro Low memory usage
Rxvt-unicode uses very little memory and takes a lightweight approach without losing many important functionalities. A single instance of urxvt takes about 6.5MB-8MB of RAM.
Pro Can be daemonized to reduce resource usage
For those who want to lower their system's resource usage, rxvt-unicode allows for daemonization. This way you can run several instances of urxvt inside a single process.
Pro Supports multiple font types
Multiple font types can be displayed flawlessly in rxvt-unicode.
Pro Supports terminal transparency
Changing the transparency of the terminal is allowed for in rxvt-unicode. This not only makes for eye candy but is also good for GUI usability.
Pro Fast text rendering
Rxvt-unicode has very fast text rendering, being able to render hundreds of MB of text in a very short time.
Pro Minimum dependencies and simple text config
Pro Unicode support
International language support is provided through Unicode.
Pro High performance
Rxvt-unicode is much faster than most alternatives.
Pro Built-in Perl interpreter
It has a built-in Perl interpreter, meaning that no install is needed. Simply run urxvtperl.
Pro Handles bold text colour properly
Pro Proper wrapping support
During selection and pasting wrapped text doesn't break into lines at place of wrapping.
Pro Minimal terminal emulator
Termite is a minimalistic terminal emulator. It does not need too many resources to run and it's designed primarily to work with window managers.
Pro Vim-like behavior
Termite supports a command mode which is very useful if you prefer to use Vim-like keybindings. It takes inspiration from Vim, one of the most popular text editors, so someone who is used to Vim's commands will find themselves at home.
Pro Simple configuration
Termite is easy to configure. Reconfiguration does not require logging out or rebooting.
Pro 24-bit "True Color" support
Termite supports true color palettes, meaning that it allows for up to 16,777,216 possible colors.
Pro Works great with a tiling window manager
Termite is most suited to a tiling window manager with a simple config file.
Cons
Con Unicode characters that are too wide are blanked instead of clipped
If a character in a backup font is wider than the base font, urxvt substitutes the non-displayable character. A large letter space will show the wide characters, but the result is not reasonably spaced. There is a patch from 2014 that the urxvt maintainer will not merge.
Con Requires work to look acceptable
Out of the box, rxvt-unicode is not too pleasant to look at. Some understanding of Xresources is required for updating its appearance. That being said, the experience of customizing it can be very rewarding.
Con In daemon mode you can lose all your terminals
Because of sharing the same process terminal windows cannot be killed without sacrificing all other open windows. That becomes even more dangerous if you use multiple graphical managers without overriding socket with RXVT_SOCKET.
Con No support yet for 24-bit "True Color"
Though this is still not available, you can download the patched version for 24bit, here.
Con Requires work to configure useful functionality (clickable URL's, font scaling, tabs)
Con Unicode rendering is buggy
There are a few references to urxvt's buggy rendering, such as unicode combining characters, which bled through during scrolling.
Con Font size cannot be changed on the fly with the mousewheel
Sometimes you may need to enlarge the font to improve readability, or shrink it to have more real estate and "hawk's eye" view of data. In rxvt you need to change the configuration file or use these commands:
$ function fontsize
{printf '\33]50;%s%d\007' "xft:Dejavu Sans Mono:size=$1::antialias=false"}
$ fontsize 22
Con No option to have a "reverse color" cursor
While you can choose the color of the cursor and the character under the cursor, there's no automatic "reverse color" for the cursor. This makes it impossible to use rxvt-unicode if you have a light background terminal and a dark background editor.
Con Cannot set specific parameters through CLI arguments
Setting specific parameters through CLI arguments is not supported in Termite.
Con Difficult to install in some distros
Con Problem correctly displaying images while using compton
Images can sometimes not be displayed correctly in software such as ranger while using compton.
Con Slow text rendering
Con Limited documentation
There's only short manpages and a README on the front page of the repository which has few details on additional configuration and features.