Hahaha I can't disagree with Lea here. In my own work, I've been consistently surprised at how nicely my work looks and functions in Edge (and hell, even in IE 11). Safari on the other hand seems to have a lot of quirks or partially-supported stuff that ends up blocking things pretty dramatically. As Lea said, there's no getting around Safari on mobile, so those shortcomings are really highlighted as you test on mobile devices.
To add to Lea's grievances about Safari, it's extremely frustrating that Apple operates in such a black box. Every other browser manufacturer has extraordinary developer relations programs in place and do a fantastic job engaging with the community. Apple's culture is the exact opposite, which I think ends up being detrimental to the web's progress. I hope the competitive nature of the game forces them to rethink their approach.