the eos m is the compact version of a 650d, spec wise very similar apart from iso and focal points.... just a bit more expensive....
I think it's overpriced compared to the alternatives. Maybe makes sense if you own Canon lenses and want to use them on it, but as a stand alone I don't see the appeal.
The Olympus E-PM2 and E-PL5 and Nex 5R models are the most logical comparisons in terms of size, features and image quality and
all of them are cheaper than the EOS-M.
Plus the Nex models
with viewfinders (6 and 7) are only slightly more expensive.
Also the E-PM2, E-PL5 and Nex 5R have the option of adding an external evf which the Canon does not.
In fact you can also currently get the Olympus OM-D 'body only' at £999 with a free 45mm 1.8 thrown in and if you discount the price of the lens the cost comes to almost exactly the same price as the EOS-M (albeit the EOS price includes a 18-55 kit lens).
With any of the Olympus cameras above you also have access to lots of decent Panasonic and Olympus lenses from an established system, whereas the selection of lenses made for the EOS-M comprises one prime (22mm) and the 18-55 kit lens.