PSA: Playing Rek'Sai top means giving up a ton of utility
I realize she's a new champion and that people want to try her in different lanes, but common sense indicates she was made to jungle. Disregarding everything else, just look at her tunnels and her ult. Her ult lets her go anywhere her tunnels are, and she can place tunnels anywhere as a jungler.
However, as a top laner, which is what I'm seeing, she loses this immensely valuable skill. I had a top laning Rek'Sai tell me that her ult "is just for getting away". Yes, a skill that's interrupted by tower shots and champion damage is made to get away from fights -_-
TL;DR Rek'Sai was made for the jungle. It's what she was made for and does best.