https://opticallimits.com/canon/canon-rf/canon-rf-24mm-f-1-8-is-stm-macro-review/
Somewhat below expectations.
Chief Editor - opticallimits.com
Doing all things Canon, MFT, Sony and Fuji
I think it's about par for what can be expected of a consumer-grade, fast, wideangle lens?
Better than the 24/1.8 or 28/1.8 lenses of yore, but not by that much.
Canon seems to have an issue with such lenses. The EF 28mm f/1.8 USM was also underwhelming.
Chief Editor - opticallimits.com
Doing all things Canon, MFT, Sony and Fuji
The EF 28/1.8 was suffering from every malady a lens could've had, at least until stopped down quite a bit. This one is better behaved in most regards, of course, but it has a few new issues (like the excessive distortion that is fixed with software but makes sharpness in the border areas worse than it could've been).
Then again, the Sigma 24/1.4 is also far from perfect (similar to its DSLR progenitor, but the 20/1.4 DN seems a lot better according to all the reviews I've read so far...)