I've been a big fan of Yakuake for a long time. It's a terminal you have open all the time in Linux that is shown and hidden, over any other windows, by a simply hit on the F12 button.
But as of more recent versions of Yakuake it has become really slow. It sometimes take 2-3 seconds from F12 press till you can type on the terminal. So I uninstalled it and tried Yeahconsole but I uninstalled it equally fast as I understood it was broken and didn't work at all despite being in the Xubuntu apt repositories.
Last but not least I ended up using Guake which not only works but also works really really fast. Screenshots here
I've had the same problem as you, and I've solved it by selecting another font in yakuake. The delay was very noticeable when using Monospace, now I've selected Dejavu sans mono and the one second delay has disappeared.
Let me know if it works for you, and spread the word! :-)
In order to notice the difference I had to reboot the machine.
thank you for the hint