Newly made 100-400 sharper at long end?

Many new owners claim that 100-400 is sharper with newly made this year, is that ture? The only one thing prevent me owning this lens is soft at the long end and it isn't weather sealed.

I own a UT copy of this lens, and I find this lens sharp at 400. Granted it's not prime sharp nor is it as sharp as the 24-105, but I certainly would not call the images soft. I would best compare the results to the 70-200 2.8 IS (the f4 is sharper than the 2.8 IMO). I would bet a lot of the soft complaints come more as a result of bad long lens technique. I'd rather have the zoom versatility and IS over the 400 prime. Weather sealing - that's a different issue altogether.

I find it to be sharp enough at the 400mm end.

Here a full frame:

Byte size: ZERO | Content warning: NOT AN IMAGE

Byte size: ZERO | Content warning: NOT AN IMAGE

Mine is sharp; I haven't been around POTN that long, but long enough to see the legend of softness be narrowed to user error almost all the time.

Grab it, if is doesn't work send it back. B&H is super-cool like that.