General 'Rule of thumb', 50x magnification per inch of aperture
More aperture = More light = more magnification for planets etc
In saying this, a different rule of thumb for faint galaxies & faint nebulae, still more aperture is always better, though lower magnifications will see fainter targets, eg galaxies & Nebulae, better and crispier then higher magnifications
Comparing 8" to 8" in different newtonian scopes, an 8" F4 is much better suited for faint galaxies and nebs & will perform poorly with planets ; where as an 8" F10 is much better for moon and planets but will perform poorly with faint galaxies and nebs.
Ultimately, $$$ will restrict all of us when it comes down to Aperture, Optic quality, Reflectivity Coatings, Configuration designs and Polishing accuracy, and of course the mount to carry them