HxH is the better manga IMO but NNT's anime was a pretty bad adaptation overall. It is rushed and doesn't compare to the manga at all.I vote HxH
I have not read both manga's but only watched the anime's.
I love the fight scenes of HxH thanks to the anime. I don't like the art. If not for the anime I wouldn't be here. Story is average as well. Then there is hiatus.
Seven deadly sins was ok at first but then i lost interest. The fight scenes looks epic but are rubbish. Story until season 1 is not great either. Manga art is no good and thats why i did not continue to read the story after watching anime.