I am sure the Merill has been improved though, but compared to the dp1 and dp2 I found the Leica x1 much more usefull and flexible regarding IQ in various conditions.
For the RX1 - sounds great in one way but for my part I think the price of a x100 or a x1/x2 would be the max Iwould want to pay for a small compact with a prime. And lets not forget that with a viewfinder and with that lens the rx1 is not really a pocket camera.
I am not sure yet if I like this size-too big for a pocket camera but too small to handle really nice and well. But for others it might be just right.
For the same money I would personally rather buy a x-pro 1 with 21 and 35mm and a rx100 when it gets small.