xKeys Pro or Desktop

I'm running 1 priest and 4 locks, and i quickly found out that one keyboard alone doesn't cut it.
So i've been looking into the xkeys stuff. The Professional is kinda expensive, so i've been thinking about getting the Desktop one.
Do i really need the 58 keys you get with professional, or should the 20 from desktop cut it ?

get the pro you will be happy. Its not that much more and you never know when youll want more keys.

Desktop worked well up until TBC. If you add another modifier key it might work.... but I also had a stick for non combat buffs.