Neither a rival nor a toy. I believe Hisoka has mixed feelings. His stated goal is to allow Gon to "ripen" (achieve his full potential), then defeat him, body and soul. Yet he also has high respect for Gon and will protect him, at least until that "harvest". We even see him as an ally during the Yorknew City and Greed Island arcs.
Being a psycho is complicated. In a very warped way, Hisoka may even love Gon (in addition to a possible sexual attraction). But it is not a love which is likely to end well.