Here's my reasoning; it has to be over 400 and less than 1000.  So there's that, but if we add in the consideration of other directives generally sticking to the x 100, then we get a short list of: 500, 600, 700, 800, 900

Then after looking at this list: https://github.com/angular/angular.js/commit/b7af76b4c5aa77648cc1bfd49935b48583419023

NgSwitch uses 800 and NgIf uses 600.

So that leaves 500, 700, 900. 

I selected 900 based on the legacy behavior of ng-controller creating a scope for use by ng-switch. I spun up a very simple plunkr [here](http://plnkr.co/edit/FtLGvmr6SuLy4oZFa6k2), but @caitp is working on what I am sure is a much better test to confirm the legacy behavior of ngif & ngswitch