Update: Got my pre-owned, verified good-copy 24 PC-E late on Friday, did some quick tests with it yesterday. Simple net is that it is a very good copy. It is sharp corner to corner at f5.6, 8 and even 11 though diffraction is visible as early as f8. It performs better at closer focusing distances, or more accurately what I would call normal subject distances for this type of lens, say the 3 to 15 meter range. In this range, the lens can keep up with the sensor almost fully corner to corner when zeroed. As distances increase beyond 15 m, resolution falls off a little and while it's visible at 100% view, for all intents will be immaterial even for a large print. On a full horizontal shift, the last 4mm or so of the corners are mushy, but good enough for sky or irrelevant foreground, just don't expect to pull usable textures from there. I need to test more vertical shifting of a landscape orientation image, but it appears that is fully usable on this lens. Lens seems well-centered, perhaps a tad better on the RH edge than the left when fully shifted. Lens has some curvature which is expected and actually welcomed by me for most of my uses for this lens. Use note on tilts, a little goes a long way with a lens this short -- in most typical cases, 1 or 2 degrees will be all you ever use. In fact, I would reco that Nikon go to a finer adjustment design for the future version that would allow an easy input of a quarter or half degree of tilt. So at the end of the day I'm a happy camper with a very usable and welcome lens added to my stable, but the reality remains Nikon needs to refresh it for their newest sensors.
And please Nikon, bring on a fresh 17 PC-E!!!