Which camera to choose , GX1 or NEX 5 N

I can just tell you my experience - and my very limited statistic.

I bought a G3 with the X 14-42 as a kit about a month ago.

I could not get sharp photos with this lens when using shutter speeds between about 1/25 sec. and 1/250 sec.
I have no problems using the Pana 20mm.

I sent the lens to service. Panasonic could not or would not repair the lens.

They offered me a replacement lens, and I asked them to test this lens before shipping it to me.

They told me, that they had three new lenses, and they tested them all. They found minor differences between these lenses, but all had sharpness problems at the mentioned shutter speeds. (They called it a "lens characteristic.")

My statistic:

DP tested at least two copies of the lens in their review af Pana. GX1 camera.
Both (all) were affected

My lens was affected

Panasonic Service´s three copies were also affected.

So out of at least 7 known lenses all copies were bad.
Yes, Panasonic should be ashamed.