For daylight, almost anything will work just fine, but it's that sunset and after where sensor quality and size really come into play like Batman. Even out Nikons have high ISO noise, so this is what surprised the heck out of me with Fuji - only grain, well into 6400, and that was quite mind-blowing comparing it to the 600. Only other thing is battery life, that all mirrorless things seem to lack in a significant sense perhaps the X-Pro and X-100 due to hybrid VF.