Since my Nikon d40x decided to die (shutter problem, shop says repair will cost more than camera is worth), I have the joy of looking for an replacement.
I was mostly content with what I could do with it so I could stay with Nikon and go for another DX sensor (for instance the D5100?). Besides the 18-55kit lenses (which I was thinking about replacing), I currently own one other (tele)lenses for it. On the other hand I am lured by the smaller size and weight of mirror-less cameras like the micro-4/3 (for instance the Lumix GX1 or similar).
Anyone else had a similar choice? Or experience?
Edit: I forgot to mention: I shot mostly when traveling (landscape, architecture, people, anything except "real" portraits) or when outdoors (hiking, climbing). Clearly, sometimes volume/weight is an issue for the latter use. Also, I realized that sometimes I would like to have a camera around for everyday street/market scenes, when I did not bring it, because I felt it was too big to carry around all day.
Edit again: Two specific specific questions I have, would be what are the experiences with respect to battery life (pictures taken/battery) and auto-focus speed. The general thread mentions that auto-focus is slower for the mirror-less ones, but how "bad" is it?