I chose the Sony NEX-5N over the Ricoh GXR M-mount because of its superior video and cheaper price. The Ricoh GXR M-mount may be better optimised for rangefinder lenses; without comparative testing it is impossible to tell. However, the NEX-5N isn't bad at all, especially when using a lens such as the 50mm F1.4 nikkor shown above.

The best thing about the Sony is the sensor of course. The next best thing is that it has full HD video. I have not done any videos yet so cannot comment on the video image quality.

The Sony NEX-5N, along with the M-mount adapter and the default kit lens is cheaper than the Ricoh GXR with the M-module. Is the Ricoh worth the extra money? I am not sure, not having used the GXR. However, having used the Ricoh GRD III I do know that the Ricoh is likely to be more photographer friendly.

There are many who dislike the fact that the Sony NEX-5N does not have more direct controls such as dials. I personally do not think this is an issue - in fact I like to use only a few settings most of the time and as long as I can access these with little effort, I am happy. I do think that it is unfortunate that Sony does not allow the soft key C (centre scroll wheel button) to be set to manual focus assist - as this is what I need most of the time. The soft key B (lower button) is automatically set to MF-assist but it is harder to get at.

In terms of ergonomics, I wish the NEX-5N was a little taller and the buttons were slightly higher so that the soft key B could be accessed somewhat more easily. It is typical of Sony to go for what I think is inferior usability in order to get some marketing points.

All in all, I am thankful to Sony for making this camera. To be able to use a rangefinder lens such as the millennium nikkor on a digital camera gives me great pleasure. The feel of a completely mechanical and manual lens is very different from the typical plasticky feel of regular lenses available these days. The rangefinder lenses are small but give you top quality images. They are a joy to own and use. 

Some other observations:

• The shutter is as loud as an SLR which is disappointing.
• The focus peaking feature is useful but not reliable for high speed lenses - to accurately focus you need to magnify the image using focus assist. This slows you down considerably. Taking pictures of stationary subjects is fine, but it is much harder to take pictures of people moving about.
• The camera is very light - the mount adapters and the lenses are actually heavier than the camera. I am glad that the camera body is made of magnesium alloy.
• The camera with a rangefinder lens such as the Nikkor shown above, is much smaller than a typical high end DSLR - but not truly portable. The Ricoh GRD-III is truly portable.
• DSLRs are superior for taking pictures of people and anything else where it is necessary to track focus. The NEX-5N is more convenient for stationary subjects especially when using manual focus lenses. 

You can see some sample images on my Millennium Nikkor page.