Irelia is better toplaner atm. If you are looking for a new jungler, Jax is better than her, his early ganks are not bad and can duel anyone in the jungle. He can beat her top, but no Irelia will fight to the death. Irelia's play pattern is to chunk the opponent hp bar with her abilities and sustain with her heal and flask. Jax doesn't have such burst and is all about sustained fights. His mana costs are higher and abilites deal less dmg, unless you go Ap. Irelia gets just Triforce and kills everyone, then builds full tank. Irelia can play vs ranged like Lulu, Gnar and company, Jax will probably feed or get zoned really hard.