I never could get onboard with constraint based layouts. It feels like someone got a little too clever and really over-solved a problem. Realistically, you want your content to look decent on small screens (phones), medium sized screens (tablets), and fill larger ones (everything else). In the case of iOS dev you really have 3-4 specific targets. CSS media queries (or 2-3 nibs with boxes and springs) solve this problem adequately. Trying to create a system of linear inequalities that guarantees perfection on every possible resolution is just asking for mistakes and headaches. I agree with the author that most of the "power" lays in a space of things you really don't want to touch.