Im not surprised. In any case, the 25 mm leica is an extremely good lens. I am surprised the low light you cannot see a difference. Shoot with olympus body and I think the pictures will be even better in low light with the IBIS.
Now that a bro told me I could adjust the pic control settings the d5100 could in the end have the edge.will test it out. One thing though the pics when view through the gx1 LCD screen looks the same quality when blown up on PC screen
but the d5100 the pics ALWAYS look wAY better in the camera's LCD screen compared to when blown up on PC screen. ON THE BODY LCD SCREEN THE Pics looks like real pro shots but on PC looks ok la. Sometimes quite disheartening. My PC screen resolution should be higher than the d5100 but don't know why like that