Its Amazing but in the middle it get little confusing.. Especially in Chimera ant arc when after episode 112 the pace of story revert to 0.25. And There is no character devolpment of Gon Freecs the main character. He looks like a rip off of Son Goku (DragonBall franchise). Kurapica, Leorio and Killua were good. Animation quality is amazing. Madhouse did the amazing job. Fights in this anime were average.. Too much explanation not needed. Mereum is one hell of a character. Hisoka is also good. Mereum royal guards were also great. But other than that most of the characters are quite forgettable.
Edit : Damn how I forgot. Phantom troupe are the best villain group you will get in the anime. And my complain with Hunter X Hunter is that they don't show us about characters backstory. Like of Phantom Troup and Hisoka. I don't know why people ignore this major thing and call this the best anime of all time. We'll in truth it is one of the best but not the best anime of all time.