The Sigma dp Quattro series of cameras is a great camera for a number of reasons. Not only is the camera one of the sharpest digital cameras on the market, but also purists will love it for its true film like qualities.
If you have ever photographed a classic Hasselblad camera, then the square format (1:1 aspect ratio) will feel natural as well as be a throwback. With this you don’t need to worry about portrait or landscape orientations. Just leave a little room to crop and you are good to go.