Get the one you like the best. [sm=thumbs_up.gif]
The Pershing is a better engineered kit and a little more complex needing some experience with R/C and the King Tiger is much easier to build but the tracks and their tension can give you some difficulties when driving in grass or a non-slip surface.
The rev feature of the Pershing is fun but you must remember how to disengage that when you want to start moving the tank. Also, the interior room is limited in the Pershing so making space while you're building is important.
You'll like both!