I deliberately brightened these during processing to try and match how bright it was outside, but I think I went too far! It is possible to use non-Sony lenses with an adapter, but my preliminary impression is that the Sony lenses are better than some people are saying. The 16mm lens corners never get completely sharp, and it has some pincushion distortion, so it's disappointing performance for a prime, but I can understand Sony's decision. If you want a bigger sensor, small size, and low price (all good things), some sacrifice is needed, and I bet that as sensors get better at handling light coming in at a sharp angle, we'll see better performance from these same lenses.
Herman, the Sony has better high ISO performance and dynamic range than MFT. Image quality is a tough one to answer, because those are components of DR, but so is lens performance, and I'm not sure about that yet. Handling is personal. I prefer the controls on my GH1, and I like to shoot with an EVF, but the NEX5 is easier to hold.