If you want an Arduino as the base, RAMPS is about the only option. All other electronics have the ATmega on board, no Arduino needed. The better known verions are:
Gen3: the classics, well supported.
Gen6: an industry product, no work needed, but also no modification possible.
Gen7: optimized for DIY and replicatability, so it can be the cheapest if you do things yourself.
Sanguinololu: Somewhere between Gen6 and Gen7, very compact.
All of them work, all use the same firmwares, all of them require the same motor specifications. The effective differences are small.
Oh, and the Prusa has 5 motors, but requires still only 4 stepper motor drivers. The two Z axis motors go into the same outlet.