Of these two cameras, the Rebel SL1 no contest. While the EOS-M is interesting, I feel it has too many issues for serious work. Plus, the lens ecosystem is too small and if you are going to use an adapter you might as well just get the SL1.
But one thing to ask, is the SL1 really *that* smaller than say a 6D with a pancake? Because a 6D with a pancake will produce significantly better results at night than an SL1 or an EOS-M. Also note that a pancake on a 6D gives you a normal 40mm lens, while a pancake on crop gives you a weird halfway between normal and tele lens.
Unless you just want all of the gear to be lower value, in which case I'd say SL1 + 28mm f/2.8 IS USM. That will approximate the field of view of a 40mm on FF and is also a higher quality lens - while not being much larger than the pancake. The IS will help with certain scenarios at night, too.
Thank you, Sir, Dear Ruined.
Yes, A lot of Think for me , Now Because Some of CR. post say that the New EOS-M with view Finder will come in the market very soon, May be the first Quarter of 2014 ??
Yes, Sir, That will be easy decision for me.
Have a great day, Sir.