i've used a friend's x2, and it is impressive. it is considerably smaller than the other cameras in this segment, yet bas the best controls of all of them for manual shooting. it is silent and the files are very, very good.
the electronic vf is only okay; it's the exact same evf as sold by olympus for less money, apparently. but i am not interested in the evf. there are a wide variety of optical vf available for various prices and exhibiting a range of brightness and quality; any standard 35mm hotshoe mount vf will work. zeiss vfs are very good value.
the trick is to deal with focus. in most cases for street use i would set this camera to about 5 feet and then just adjust my position and shoot. it is possible to use af either directly on sedate targets, or to af on an inanimate target the same distance away (even if in the opposite direction), then swing and shoot. (contrary to some reports, the af is not glacially slow, but it is more leisurely than we dslr shooters are accustomed to.) it is even possible to adjust focus manually on the fly, but this is tricky and difficult to get right.
mainly because of the difficulty controlling focus quickly and directly, personally i have little interest in the camera. (i am fortunate to have better options, also.) but i would probably get one of these before i got an x100, if it came down to a choice between those two, and it might even win out against the nex offerings. however, i strongly suspect the new sony rx1 will trounce the x2 roundly in all respects save size. if i had the money to spend for this kind of thing and wanted a camera in this segment, and could wait for several months for availability, i'd go for the sony, unless something changes.
the more practical alternative for most people would be to look at the various m43 offerings. they are not as small, but they aren't large, and they're good value for the money as far as street cameras go.
you might check out the branch of the street photography exchange thread which begins here:
if you are interested in some further observations regarding this cameras in approximately this class.