Srin bought a Canon DSLR on Leo's recommendation five years ago and he's ready to move to mirrorless. Leo says that's a good way to go and he recommends the Micro Four-Thirds because there's a broad range of lenses, and they are smaller. Leo likes the Olympus EM-5 and the EM-1.
Sony is another option. The NEX line is superb and have APS-C sensors. The A7 has a full frame sensor as well. Leo does say, however, that there's a tradeoff with mirror less in that it has a video viewfinder, and not an optical viewfinder. The other tradeoff for Sony is that they have few lenses at the moment and using a lens adapter will slow down the focusing. But they're great cameras.
Canon has also added a mirror less camera, the EOS M, but they've been slow to the party.