Hacker News Reader

I would say the opposite: After a small initial hump, flexbox is actually very simple for what it gives you, but it's ultimately fairly limited. It's not up to implementing every kind of grid layout cleanly, and it's not even in the same ballpark as constraint-based layouts.

I'm no CSS expert, but I personally find it incredibly easy and intuitive compared to the usual CSS alignment nonsense. Floats? Table display? Inline block?

Flexbox is the first CSS layout feature that makes me feel like I don't have to harness an army of hacks to get anything done.

There are still layouts it can't solve, for which I'm using Javascript to manually calculate the size of elements

There's a learning curve, but it isn't as fragile as the set if margin and position hacks that were standard before. Those old hacks are still used for supporting old browsers (IE8 and before), but flexbox simplifies things once you grasp it in applications.

I find it no more complicated than things such as figuring out things like clearfixes were in the beginning.