Which camera is more suitable for a professional photographer? Is it nikon or canon?

Reviews about these cameras

If you think it matters, you aren't a professional photographer, and probably never will be.

Sony have targeted the professional sector with a series of full-frame bodies, and are learning the hard way what Pentax learned in the days of MF - pros are traditionalists who stick with one or the other and no third manufacturer has a chance. The Pentax LX was a world-beater, and amateurs who could afford them snapped them up - but the pros stuck to the Nikon F3 and the Canon F1n.

Neither brand is superior to the other but people stick to what they like.

Andrew is right, especially in his first sentence.

As a professional you would know without having to ask complete strangers

It's the photographer that creates memorable images not the camera!

Both have their own pros and cons. Really depends on what you want to use it for. Andrew was completely correct with his answer so i won't say any more.

If you an actual "Professional Photographer" you wouldn't be asking this question to begin with because a "Professional Photographer" already using one or the other. Your question leads me to that you're NOT a "Professional Photographer"

Neither! You need to handle these cameras and include Pentax in your search Specifically the Pentax k30 (best purchased in "kit' form with the 50-to-200mm lens!). I chose Pentax over Canon when I reentered the world of DSLR's. The viewfinder is less busy, the stabilization feature is built into the camera body not each lens. This makes available lenses from earlier days even film cameras, that will fit the current Pentax digital single lens reflex cameras. I just liked the "feel" of the camera and location of controls, etc!