R.O.J.A.K. is a pretty solid character! It teaches a lot about juggling your opponents around with combo platter of different attacks rather than just blindly mashing the primary attack button lol
However, the same can be said too about Balzarr. But if I were to compare the two in terms of difficulty, Balzarr is most definitely much more challenging to master especially due to his lack of long range attacks, whilst R.O.J.A.K. (AKA The Mighty Warriors) on the other hand, is far more easier to master, and for less experienced players, I would definitely recommend using them first if they are looking forward to using a character that can do lots of combos! And hey, it's a freakin' Sentai Mecha too, who doesn't like that, eh?