Espeon Zen Headbutt

they are both good imo

I think ZH is better EPS than C, so it gains value if you have a good charge move. Since Future Sight is one of the best charge moves in the game, I would bet that's as good as C/FS, perhaps better, and probably close enough to not matter offensively.

If you're looking for defense, though, Confusion will definitely be better.

I still waiting for a good eevee to evolve to espeon, but in my exeggutors confusion is much better than ZH. eggy can take more hits than espeon, so maybe ZH is better for you.

ZH + FS is better