Jev,I have been happy with the Olympus micro four thirds system with a 2 times lens crop factor, [Panasonic uses same system and lenses are compatible],the mirrorless systems are great for landscape ,nature,type photos,especially if weight is a factor.The system weakness as previously mentioned is for fast moving sports or complex studio flash systems,apart from that it is all good.I find the electronic viewfinders great in low light focusing situations especially with slower[f3.5] legacy lenses ,and the real time adjustments with EV settings and colour balance with EVF viewfinders very good.In short these cameras have matured to the point that many professional photographers are using these systems now,regards Nick.