[PKay (Peter)]

Now this is interesting.
Since this is a comparison thread, attached are 3 images.
(Hover over each image to get the right one)

The first (Seagull_4inch) is using the 4" EON refractor.
FOV = 110' X 83'
56 of 240sec subs = 4 hrs integration time. Cropped

The second (Seagull_12inch) is using the 12" reflector.
FOV = 40' X 30'
14 of 240sec. subs = ~1 hour integration time.
(this scope has a badly corroded mirror)

The third is all of the above images integrated together.
This meant the FOV became the smaller of the two.

The most obvious outcome is the bigger scope gets more detail in a fraction of the time, however both scopes can arrive at pretty much the same result.