It relies on the QT widget toolkit, and has dependencies to KDE.
At one time it had the distinction of being the fastest terminal emulator due to some intelligence code which cut down on the amount of text written to the screen while scrolling. Konsole is from the KDE project, and like all things KDE, it has tons of knobs to tweak. It uses the GTK+ widget toolkit, and it has some dependencies to Xfce. It's simpler then the other two, but it's mainly missing profiles, which the other two have, which I don't use. Xfce Terminal is a personal favorite of mine. The decision is mainly going to come down to which toolkit you like and which dependencies you can live with.
Xfce Terminal Emulator, Konsole, and Gnome Terminal are good terminal emulators, and all are going to have tabs and keyboard shortcuts.
