Guake's appearance is very customizable. From the transparency to the width and height of the window.
You can also choose what interpreter to use (bash is the default) and also things like which key to choose for toggling the terminal window.
After (re)booting the system, Guake does not boot automatically. You need to open the application and then press the key to make it drop down which is a bit annoying when you want to get started quickly and don't want to press two different keys just to open the terminal.
Guake's appearance is very customizable: from the transparency to the width and height of the window. You can also choose which key to use for toggling the terminal window.
Yakuake is a drop-down terminal. This means that you can press, for example, F12, and it slides downward from the top edge of the screen. After you are done with it, you can then hit F12 again and it slides back on top.
Supports tabs and working with several tabs is very easy. By default: to open a new tab press Ctrl + Shift + t and to move through them: Shift + left/right arrow.
You can easily split any tab into different windows and run several commands at the same time then monitor and change them with ease. You won't find this feature in guake or tilda!
While not an issue if using KDE, when trying to use this terminal in other desktop environments or window managers, there will be a large amount of dependencies tied to the app. This makes for a large install size. For those trying to keep their desktop lean, this may be an issue.
UPDATE: It will probably be ported soon (I think they might do it by Plasma 5.6).
Yakuake still has not been ported to KFrameworks and as such pulls KDE4 runtime dependencies with it. This might become a problem when KDE4 is dropped from Linux distributions (e. g. Arch Linux).
Like other applications included in the Xfce package, this terminal emulator is very lightweight and doesn't require many resources to run. This makes it perfect for systems that have low specs.
Suppose you have a dark background with a light cursor and light foreground color: the light cursor will cover up whatever character it is on, so that you cannot read it. There is no option to set the foreground color for the character under the cursor to what is normally the background color. Such an option would allow you to read the character under the cursor.
It is possible to split the terminal window into several areas. Additionally, you can re-size them as needed. Multiple windows and tabs are also supported.
You can type at the same time to any number of arbitrarily grouped terminals. (Or all at once, or only the focussed, all switchable with a shortcut or menu item)
Unless this option is disabled (it's enabled by default), Terminator will only run the first instance as a process, when it's run again, the DBus server will simply open a new window using the old process. This helps a lot with reducing resource usage.
If you have a compositor you can use true transparency. You can also have a fake transparency where an image can be used as a fake desktop. Both of these can be tinted with the background colour too.
Terminator functionality can be extended via plugins. Examples:
Custom commands
URL handlers (on top of common ones) for apt, launchpad, maven
Logging output to file
Terminator has tabs, drag and drop re-ordering of terminals and lots of keyboard shortcuts to help. Also has an extensive preferences window, or if you have to, a plain text config file.
Text search in Terminator does not highlight matching patterns when found. It just shows the row containing one of the matching patterns at the top of the terminal. This way text search is still usable, but not the best.
To achieve a large amount of speed, gnome-terminal has to use a relatively large amount of memory to run. It may eat up to 15MB-30MB per instance, depending on the task it's doing.
Multiple terminals are managed from one gnome-terminal instance, that takes up about 45 MB. Adding on other instances (with 10k lines of used buffer), each terminal requires about 16MB of memory.
When using the GNOME Terminal if you have long lines of text inside it and then you change the window, the text will also automatically update according to the new window size.
There are tons of customizations you can make: from adding colors to text, turning backgrounds transparent, setting the size to be "maximized", toggling scrollbar on and off, adjusting orientation/borders/animation, etc.