Did you pre-order the lens already ? I'm contemplating to do so... or wait until some user reviews will come online. I have no idea if it will get sold out immediately in April or how many people are waiting in line to get this lens.
I've put a "soft" pre-order in (i.e. I've not paid anything!). But I've been looking at example raw files from the DPReview site and also at MTF charts, both of which tell me that it's not a particularly sharp lens. Look at these:
Those edge figures are pretty weak, hovering at around 1000 lpmm, and actually much worse than the centre at f22, which is well into severe diffraction territory.
And look at this 100% edge crop from one of the DPR samples:
Translate that to some foliage at the edge of the frame and I think it'll look like mush. But, it's in poor light, hand held, ISO 1250 - so maybe it's an unfair conclusion.
Or this one from the Digital Camera World review - 28mm, f4, ISO 100:
Not only very mushy, but there's purple fringing aplenty!
It's strange looking at reviews because most are hugely positive, including about sharpness. The PetaPixel review (Jordan & Chris) is an outlier, where they basically say it's very compromised so far as sharpness is concerned. My sense is that most reviewers are "creators" who are judging it mostly for video where I'm sure its sharpness is absolutely fine. But I think for photography on a hi-res sensor its limitations will be all too obvious. I really hope I'm wrong, but until I can do some "proper" tests I won't know. It's annoying that all these samples are just random snapshots - ISO all over the place, lack of clarity on where the focus point is, handheld, ...