Back when Chrome was the shiny new thing, Firefox was taking a downturn, I think it was around version 50 or something, as they wanted to update something that would break compatibility with a considerable number of existing themes and plugins, including my then favorite, NoScript.

For some reason, the UI of Chrome was never my cup of tea, all those round edges and auto-hiding buttons (maybe these were later additions?) annoyed me to no end.

Yeah, all my bad experiences with Firefox from back in the day were completely gone when I switched back to it a couple of years ago.

I can't use the Internet on Mobile without an adblocker. The user experience is totally unbearable

Better for MS non-standard things? Or better how?

All browsers had non-standard things back then, to the point where many sites had two versions: An IE version and a Netscape version.

Believe it or not, back then Internet Explorer was the most standards-compliant browser. It was the first browser to implement the DOM and CSS based on relevant W3C specs (Netscape was backing JSSS instead).

Many features we take for granted these days came from IE. Drag and drop, the JS events system, iframes, rich text editing, clipboard access, AJAX (dynamically loading content on the page without a full page reload), visual effects like transparency and gradients, all originally came from Internet Explorer.

The CSS box-model in IE6 (including margin, padding and border in the width of elements) was wrong because the CSS spec hadn't been finalized by the time of its release so Microsoft used a draft, and it changed from publication of the draft to publication of the final version. Many years later, people realised that IE6's model was actually the better model, which is why every browser supports it now via box-sizing: border-box.