Best way to discuss the lens is to look at the pictures. In review pictures I did not find anything retro or lomo. As for sharpness, it is hard to judge for it by pictures at high iso and handheld. According to Huff, Canon R doesn't handle this lens well, but Panasonic S1 does.
This is new trend in reviews, which I don't like, but lens official sellers do
. M mount lens on non Leica camera. I don't think it is the same, I don't take reviews like this as something I would see on my RF Leica.