Yes I’m exaggerating but why is this a thing in so many refractor discussions on the web?
Why is It that so many will do a comparison of a 4 inch APO and an 8 inch SCT or Newtonian and think that they see more in the APO? Limiting magnitude and resolution will surely be better in the larger scope. Am I missing something?
Why do they do the comparison? Easy. They have decided to spend their money on a smaller, hopefully high quality scope rather than a larger, perhaps lower quality scope, and they want to know whether they are making a wise choice. Hence, the comparison. Nobody buying a high quality 4" refractor is thinking, "Should I get the Takahashi FC-100DL or will the Celestron ExploraScope 114 meet my needs equally well?" They are similar in light grasp and resolution, but no experienced observer actually struggles making a decision between these two. But, compare that FC-100DL to an 8" Edge HD, and suddenly you are in the same ballpark in terms of cost (depending on the mount you select for each, of course). This is something that a reasonable, experienced observer might well debate, and either scope could be a reasonable answer depending on one's typical seeing conditions, available time for observing, convenience requirements, the objects one likes to view, willingness to performance maintenance tasks like collimation, etc. And, no, it doesn't require that a smaller scope be able to "break the laws of physics" and out-resolve a significantly larger scope in order for one to prefer the views in the smaller refractor. My 5" refractor does not, can not, and will not out-resolve a decent or better 8" reflector under most conditions. I wouldn't expect it to--too big a gap in aperture. It doesn't have the light grasp of an 8" reflector under any observing conditions. But I still prefer its capabilities to those of any 8" reflector.
Look at it this way... That same 5" refractor when coupled to a CCD camera will easily and consistently show me dimmer objects with much greater detail than any 8" or 10" reflector with an eyepiece. So why would I ever choose visual astronomy? I can't see as much when I am observing visually, so clearly astrophotography is better, yes? Vastly more resolution and light grasp with a CCD than with my very mediocre scotopic vision, regardless of the aperture.
How often have you seen the bridge of stars, gas, and dust connecting M51 to NGC 5195 with your 8"-10" reflector? Be honest now. What about the 15th magnitude central star in the Ring Nebula? How often do you see that with an 8" SCT? I can get more details on M51 or the Ring Nebula--and color data at that--in a single five minute exposure with a 5" scope under my urban sky conditions than any visual observer will ever see with a 8" or 10" scope from the darkest of dark sky sites. And yet, lots of people prefer visual observing to astrophotography. Some want the simplicity of visual observing. For some, they like the visceral nature of looking at the actual photons rather than a reconstruction of them on a computer screen. Some prefer the challenge of the physical observation over the challenge of the computer processing. Neither observing approach is any more "right" or any more "true."
By the same token, I think it's silly for owners of 8" reflectors to say they are intrinsically "better" than 4" refractors. Better for what? What do you want or expect to see? Under what sky conditions? Just as it's silly for refractor owners to say their smaller scopes are clearly "better" than a larger reflector. Better for what objects? After how much cooling time? Under what kind of skies? We all have slightly different observing goals and are excited by different objects and different challenges. Some people enjoy spending an hour or more on M13 trying to take it all in, while others would rather check it off of their observing list and move on to something more "challenging". The reasons for the comparison are pretty straightforward--similar budgets with very different strengths and weaknesses, so lots of people want to compare. The competition between reflector and refractor owners, though, is kind of silly. Pick what's right for you, for your budget, for your location, for the objects you like to look at and get out under the stars. Me? I generally prefer astrophotography over visual because I can see so much more, but that doesn't make my choices any better or worse than someone working to complete the Herschel 400 with their 12" Dob.