via 1001 Noisy Cameras: A Korean Blog, StrongArm's Camera and Lens Review has posted an ISO comparison of the NX10 and GF1. Initially the test was posted in Korean only, using the kit zoom on the Samsung. The test has been updated to feature both pancake lenses and a description in English. This was a JPEG comparison, with a pre-production NX10. Furthermore, while the Samsung lens was used at f/8 (not much diffraction effect for APS-C), the Panasonic was at f/10 (significant softening due to diffraction at this setting with :43. Still, the results are interesting. See the comparison here.
From what I can see, is that Samsung is doing what they've always done, heavy NR above ISO 400. To me, the panny is retaining some detail the samsung isn't. It almost seems to me, with entry level APS-C cameras vs mFT, that the only advantage is higher dynamic range. For ISO 1600, I'd take the GF1. At ISO 3200, I'd keep neither.