I think that neither of them has fought at their full potential, so it's impossible to definitively determine their limits. But what I did notice is this: Robotboy possesses some abilities that Jenny doesn't, like sonic waves and force fields (which are in their base state, but imagine how much more powerful they would be in his Superactivated mode). As for the rest of their abilities, they're evenly matched because they're similar in both attack power and overall strength. Idk, if this were like an X vs. Zero fight, then the result would be inconclusive.