Due to (the image quality of FF, the 100mm L), and the ISO advantage, apparently FF is simply better, correct?
Actually, it's a bit more complicated.
Because of the bigger sensor (and thus higher focal length), you will need to take a smaller* aperture for the same DoF. Smaller aperture = need to take higher iso/lower shutter speed. But that's compensated by the bigger pixels, which give you better high-iso performance etc
*smaller= higher f-number. When the aperture you count in mm's (or whatever) is the same on 2 lenses, the DoF is always (actually, not always, there are other fysical variables...) the same. The purpose of the f-number is not to tell something about DoF, but about how fast the lens is.
Ummm...no, it's pixel density as stated, not sensor size. Compare the 5DII to the 20D, FF and APS-C with the same pixel density - does the 20D have a 'magnification' advantage? No.
It's about the raw magnification advantage. Not the advantage you get with post processing or digital zoom
. It's obvious that a recent camera has a higher pixel density, better high-iso performance,... then a very old camera... Do you also compare computers of 1990 with computers you can buy today? No?