In addition, did a comparison of the manga/2011/1999, and the 1999 did scenes much more slowly...which I actually quite enjoyed. Scenes like Leorio + Gon were really given more time to develop together so the early character development is actually better IMO. Also added/changed scenes like the assassin revenge girl after Killua in the 2.5 phase was actually fairly tense and interesting, as well as the way Gon forced Netero to use his right hand was more interesting and exciting too. Then things like clips when Menchi talks about Hanzo and it clips to him doing push-ups - that felt more thematically cool. But 2011's dialogue is more loyal to the original and a slightly better adaptation at the material, like having Hanzo's goal as a hunter and what Tompa did. But things like 1999 Killua's bombs and the added phase on the shipwreck island when they fight off the hurricane (and was the first team up of Hisoka saving Gon and Illumi aiming Kurapika) was brilliant and awesome in hindsight. So yes, 1999 wins more in my heart.

Another small thing is that I think Gon's restriction power up against Neferpitou and Nanika's wish granting were the biggest "stretches" that I didn't enjoy, and those arcs aren't in 1999. That said, 2011 does have more arcs and episodes, and seeing stuff like Leorio almost succeed Netero and Ging's words of wisdom to Gon were nice, as well as Killua's growth and eventual goodbye.

Both 1999 and 2011 are great though, but I'd say 1999 is more enjoyable. I have however had a newbie friend try both and was told 2011 is more swallowable because of its faster pacing and more recent animation. But to me, I think I'll probably always hold 1999 in a higher regard.

However 1999's halfway point betweens of a colored face transformation is more applicable to the manga than the learning the HxH language and I prefer its classic feel and look. IMO anyway.