It depends what you're used to. I too purchased the body and the M-mount last year for occasional street photography use to also complement my D700. When I looked at photos taken I immediately saw what you referred to here in your comment, i.e. small amounts of noise even at lower ISOs. At higher ISOs (> 800) you really see noise creeping in (look at dark areas in the image), I just can't get past that. That's marginally better performance than my older Panasonic LX3! I was disappointed to say the least.
Overall in my view, this camera while really nice, is behind in many respects compared to cameras by the competition (Nikon D7000, Pentax K5, Fuji X100, etc.). It is not quite the issue of purely technical specs either, as some one mentioned in response to your question, photography is more important that checking out numbers, very true! BUT, certain things aren't acceptable anymore in this day and age and the shortcomings of this camera are among them. When you are among the only manufacturers who don't meet the high specs, we got a problem.
M-mount module, while hugely convenient for using L/M mount lenses, it suffers from a number of shortcomings that have been discussed here and elsewhere over the past months. If you decide to buy it, you will no doubt enjoy the experience ( I have and still do), but don't get rid of your better gear yet! I still use my D700 for all my serious work. The difference becomes even clearer when you print your photos A4 or larger. You will know right away which photo came from which camera! It's that obvious. I wish Nikon would develop something like this (APS-C or FX) with D7000 capabilities inside! Someday...