There was a time when I was 100% Leica, M & R, with lenses from 21 to 560mm.
Unlike the Leicaflexes, the R bodies were mechanically only acceptable in terms of finish, though competitive when it came to specs. Throughout the years, I lost a few plastic levers or lever elements...
But the lenses still were first class.
Then came AF and digital, and Leica dropped out of the race, for several reasons. Mostly lack of money due to the wrong strategic decisions and poor management.
I bought the Canon 5D III and was more than happy. Turning back to Leica in mirrorless age? No chance, they don't have the lenses I want: No TS, no genuine Leica telezoom, no recent standard zoom. I know, there are some Sigma options, but Leica's strength is their lenses, I don't buy Leica in order to use lower quality optics. I know, Leica's longer teles weren't exceptional, but their moderate focals are superb!
And Canon's longer focals are great, Canon's AF too.
Yet, If I didn't need those lenses, I'd certainly get the SL 3, for its wonderful Summicrons and its body finish. Since I'm only occasionally into sports or wildlife, AF is not of utter importance to me, provided it's better than the SL 2's.