i recommend checking out the 1999 one. i personally liked it more than the manga and the 2011 version. it also made me actually like the main characters and fleshed them out in better and more interesting ways than was done in the manga/2011 anime. killua and gon are more like siblings than an unhealthy co-dependant relationship (well, more like dependent solely on killua's end..), and gon is less of a little douchebag. kurapika and leorio are more fun to watch too, and they don't feel like empty characters to me the way they did in manga/2011. i wish they could have made it to the chimera ant arc, but alas. admittedly i haven't watched the greed island OVAs of the 1999 anime yet, so i can't really speak on the quality of those. greed island was easily my least favorite arc of hxh, so i'm intrigued to see if they could make it more bearable or even likable to me.

aaaanndd i typed all that out without reading your second post... oops. i'm keeping this here for other anons who have not yet seen it though. i highly recommend checking it out.