A Pentaxforum user (Click here) had the luck to get and test the new Panasonic Nocticron 42,5mm f/1.2 lens. Many image samples and aperture tests can be seen on his Flickr page (Click here). He writes:

It’s quite large and heavy. I’d say the barrel is larger around than the 75, and it’s definitely a bit heavier. The whole thing is made of metal, and there’s an actual aperture ring with nice click-stops (though it doesn’t appear to function with my OM-D). The hood is super long, and also made of metal.
AF is pretty quick and very accurate. Bokeh is great for m43. Seems very sharp wide open, though there’s a loss of contrast. Some green LoCA, but nothing major.
Also confirmed that the aperture ring works on Panasonic bodies, but not Olympus. I assume this can be fixed with a firmware update.

Still no word about price and exact release date but it’s easy to guess that Panasonic will finally release it at the CP+ show in February.

As you know some people are arguing about the Olympus 12-40mm internal pastic mount. Well Roger Cicala from LensRentals debunks the myth saying “metal mount is better” or “professional lenses have always metal mounts”. With many pictures he shows how famous lenses like the Canon 35mm f/1.4 L, Panasonic-Leica 45mm, Canon 24-70 f/2.8 L Mk and so on do actually have a plastic mounts:

Looking at 7 years worth of data involving around 20,000 lenses I can’t find any suggestion that plastic mount lenses, in general, fail more than metal mount lenses. Sure, there are certain lenses that fail more than others, but not because they have a plastic mount.
Obviously a few Olympus 12-40mm lenses have broken at the mount. It may be there was a batch of badly molded mounts. It may be a design flaw. It may just be random chance – a few of everything break. But it’s not just because the mount is plastic.

Interesting read!