I'm currently using Fira Code because I love coding with ligatures. In VSCode I'm using the color-theme Cobalt Next which is a bastardization of Wes Bos' Cobalt 2 and a theme called Oceanic Next.

The screnshot shows the ligatures (observe the triple equals and the arrow-function) and the theme. I also code with visible whitespace (not in between words but before and after).
I know there is a Fira Code + iScript mashup to achieve the same concept as Operator Mono , but I haven't tried it yet. I love the concept though.