[throwanem]

As a Firefox partisan since back when it was still Phoenix, of course I'd argue it was IE 5's box model that sucked. But the real problem is that there wasn't one box model that behaved identically across all the popular implementations.

[WorldMaker]

The old Netscape/Phoenix/Firefox box model had borders take up half-inside half-outside and doing any sort of math with it and getting things to align at all was terrible effort in CSS.

I love Firefox to this day, but mathematically the choices that box model made made sense as easier on the renderer but was awful to work with for the web developer.

It's great that we have the choice between box models today and their behavior is better standardized. I know if you surveyed CSS in the wild you'd find most CSS is written for the IE box model (border-box) and yet it is funny that that is the one you have to opt-in to because that adds to the overall impression that CSS by default is broken and needs reset stylesheets and boilerplate.