What would I obtain if I wanted the best planetary instrument for visual use ?
I like to keep my feet on the ground so a quality motor driven premium 16" or 18" F4 Dob Newt with low profile focusser,well ventilated thin mirror, below 20% obstruction , and a 2X Televue Powermate plus Clave Plossl eyepiece , would be somewhere near the top , but below the 16" Apo refractor which I could never afford
The larger aperture will yield a whole level of detail, via differentiation of colour in features by being able to maintain a healthy exit pupil for colour perception- regardless of the qulity of the seeing. An SCT would be near the bottom of my list of choices for all the reasons set out in this thread. A classical or dall -kirkham cassegrain would come in below the Newt as it has a faster aspheric primary, larger obstruction , and an extra optical surface .