Jax is a champion that is rated hard to play, I do not think that is correct, he is easy to play and OP enough. One of the first characters I tried when I started with LoL (Master Yi) was Jax, and after lvl 6 (in-game) I knew when and how to use Jax's abilities and and what build he should have, after a little help from the Recommended page.
I do not always use the build shown over, but I've made it as a set and I use it in most of my games with Jax.
My opinion is that Jax is too easy to play, so I don't actually play him so often, I test new champions for the most. After you've played 2-3 beginner bots with him you will probably understand how to use him, he is most OP lategame, such as almost every champion (exept Kha'Zix).