What's the best brand and model for a mirrorless camera?

Right now the Sony A7 series is the best on the market for stills. The A7S is the best camera period for shooting at high-ISOs, the A7R has 36MP for the highest resolution out of any mirrorless (at the expense of more noise at higher ISOs) and the A7 is a happy medium at 24MP for those need to print larger than what can be done with the 12MP form the A7S, but still want better ISO performance than the A7R.

The Leica is an over-priced extraordinarily well-built jewel of a camera. Quite frankly, you will get better image quality with the Sony A7 with a variety of lenses form Zeiss, Leica, Nikon, Canon, Pentax, and Mitacon than what the Leica can do. With the money you saved, you can buy a used BMW M3. The $900 Mitacon 50 f/0.95 outperforms the $11,000 Leica 50 f/.095, for example.

Sony are the big boys, but Panasonic and Olympus are fairly good too. Nobody with more than three brain-cells wastes time on Samsung.

While I have a low opinion of EVIL models, the old rule is still the same; the best camera for YOU is the one that feels right in your hands.

The Leica M9

The Sony A7 series (35mm sensor).

SONY a6000/a7r/a7s, olympus om-d e-m5 mark ii, and panasonic gh4