You know this is a question that keeps cropping up because we hate the weight and bulkiness of our gear. I am currently in Thailand soon moving on to Myanmar and then Vietnam and the weight of my gear has already put me in pain. So I understand, I really do, the gear is a pain. But then when I look at a csc or mirrorless camera I am so underwhelmed. I do get to see them, people bring them to class so this is not an ill informed view but they just don’t do what a REAL camera does. Maybe if you have never owned a dslr you would not be disappointed but if you have you should seriously spend some time with one of these Johnny Come Lateleys to the game before deciding to ditch your old system. Find a camera shop, if you can, T4 Cameras in Witney are the last in Oxfordshire and really do more than just hold it, put it to you eye, see how it feels.
Anyway enough of my bias, here is a very good article on Digital Camera World that puts two of the heavy-weights against each other

There are highly attractive ‘all-rounders’ in both camps: cameras that don’t go overboard on megapixel count, yet aim to take everything from portraiture to landscape photography in their stride.
Two of our current favourites are the Canon 5D Mk III SLR, and the mirrorless Sony A7 II from Sony’s ‘ILC’ (interchangeable-lens camera) stable.
A major factor in choosing any ‘system’ camera is the depth and breadth of the system itself. You’re spoiled for choice when it comes to lenses and other accessories for the long-established line of Canon SLRs.
Sony’s mirrorless cameras are a much newer proposition, especially when it comes to full-frame models, but the range of compatible E-mount lenses has grown over the last couple of years, and an adaptor is also available for fitting A-mount lenses.
READ MORE HERE