She's a very heavy snowball champ, and if you can get even a small advantage, you can win the game off of that if you know how to play it right.
Being set back does suck, but that's true of any assassin.
I'd say she's definitely worth learning, she might even be one of the top soloQ junglers atm. In pro play, she'll probably be harder to pull off but I still expect her to be seen.
I will say that before 6, it's true that shes pretty weak, however even for her, a super pushed lane can easily mean a free kill. Other than that, you should generally avoid straight-up ganking and fighting the enemy jungler, and try to focus on farming for 6.
If you ever play against an experienced Eve, it's pretty much a nightmare because she can just run the entire map post-6.