I started using Atom and switched to VS Code and there was a very noticeable difference between the two. I just fired up Atom again and it still lags behind VS Code.

Thats C++ vs JS.

VS Code is using Electron just like Atom.

Seriously people wouldn't even know it unless they told people. I hate when the community black lists a technology. I remember when Mono was the M$ Trojan Horse that would destroy the Open Source / Free Software movement.

How do ligatures work with characters per line indication, would 81 character line with a ligature make it 80 characters visibly?

It doesn't alter the characters per line indication, so it doesn't mess with debug or syntax error messages if that's what you mean. The difference is only in the presentation, but "under the hood" it's still two characters. In Atom, with Fira:

* typing => turns into the ⇒ glyph automatically

* it still counts as two: a new document with only ⇒ in it and your cursor at the end reads properly as "Line 1, Column 3"

* visibly, if you're using a monospaced version of the font, it looks like a single character. otherwise, the "optical" width is completely arbitrary just like a regular font

That would make keeping your code max 80 characters long more difficult since with ligatures it might look less - and text editor rules can't help.

Sadly no and from what I remember the dev said that due to how Sublime does text rendering it isn't easy to implement so won't happen anytime soon. A real shame as like you I love Fira Code. Works in Visual Studio, Qt Creator and IntelliJ IDEA perfectly.

I learned something today. I was not even aware of ligatures.