This is a loaded question. At the beginning of the series, Hisoka is Gon’s clear superior. However, as each arc passes and Gon grows stronger, a fair line-up between Gon and Hisoka seems to appear.  Ultimately, if Gon learned to master or develop his special Nen powers quickly, he could give Hisoka a run for his money. But as things stand at the end of the show, Gon still needs to grow a bit before he could beat Hisoka.