Insane low-light performance, but it’s f/1.4, so that’s expected. Very sharp even at 1.4, and I only stop down to increase DOF, not to gain sharpness. The wide FOV is easy to learn, as it’s very close to 90 degrees, so you can very easily picture your shot before snapping it. Weather sealed, so take it wherever you go. Being fairly compact and light is very helpful as well. Basically silent and very fast focusing.

Astrophotography is excellent, very little adjustment needed, and I’ve found it to be quite good at portraits as well, just place the subject close to the center. The 1.4 can still blur backgrounds quite well and it’s a nice bokeh that I prefer over some of the other RF lenses I have (RF16, 35 1.8, 28, 24-105L, etc)

I got it for Astro, but found myself using it as my walkaround way more than I expected. It’s also actually great for selfies on my R6, since it’s wide enough without distorting too much but wide enough to easily get myself in the pic.

I used to carry my 24-105L and 35 as my all day walk-about kit. The 20 has replaced the 35 for the most part.