They're both honestly as great as each other. Naruto's fighting is less ridiculous, although recently in the series it's beginning to become more and more so. In any case, the fighting in Naruto is much more snappy, doesn't take such a massively long time, and is pretty damn tactical at parts (remember Naruto vs Pain, and Naruto disguising himself as a Rasenshuriken to counter the jutsu shield)
HOWEVER, on the DBZ end of the spectrum, over the top and hammy as hell just WORK. In Naruto it's not so fitting I don't think, but in DBZ when you have guys with golden spiky hair and hence muscles everywhere, it's just very fitting! Not to mention the lasers and destruction; Vegeta's final flash, nuff said. However the trade-off is those massively draggy power up scenes filled with grunts and shouts and the random huge pointless dialogue.
So really, I think they both add up about equally. But if I had to pick a side, it'd be DBZ; just the flying through the air and the fast paced fighting always gets me pumped.
