Pokémon X/Y or Sun/Moon?

Both are relatively enjoyable to playthrough as a game, and you should pick whatever you think is best. That said, Moon is in my opinion far superior to x. Not only is there more story, it's loads better, and the characters are all well developed. As for X/Y, while the plot itself is interesting, the characters are generally bland and uninteresting. Take the rival for example, they have almost no personality. Plus (in my opinion) Moon has a far better soundtrack. In terms of pokemon avaliable, both have pretty good options, and it shouldn't be too difficult to build a fun and well rounded team. THis is just my opinion too though, don't take it too strongly.

xy is boring but it has the elemental monkeys
sunmoon is fun but it has no elemental monkeys

what do i do

To me X and Y had a lot of charm (played through both versions and enjoyed it both times) Sun / Moon was held back by the lack of diversity and bland characters/story in my opinion. I will be playing through gen 7 for the second time soon so my opinion may change