Blorf: I'm planning to upgrade soon and I've been considering the A77 which has a similar pixel count on a smaller sensor. If it has the same number of pixels on a smaller sensor shouldn't the image come out sharper? I've never seen pixel density addressed in a review and I'd like to know how it affects image quality.
The FF sensor (vs the APS-C sized A77) have more surface area to receive more light and image data. I'm sure someone more sophisticated can explain it better, but suffice to say that the result of a FF vs APS-C from the same company with same processor, differing only by the sensor... the FF will have less noise at higher ISO (sometimes considerably) and virtually always have sharper images even when using the same lens and setup (ie; tripod, shutter release, camera settings).