Hi Bob – I hope you don’t mind me wading into the debate. I have a number of refractors and Maksutovs which I mainly use for visual planetary observation. The central obstruction in the compound telescope does make a marginal difference in image contrast but detail revealed remains largely the same. Where the Maksutov scores is in the physical convenience of using a shorter tube. I don’t use diagonals, much preferring the ‘straight through’ approach, and certainly following a planet when well north of the celestial equator can make for some interesting times, all the more so as I’m no longer in the flush of youth! The refractor I use the most is a 120mm aperture Skywatcher achromat which with the factory focuser changed for the far superior Crayford type, gives crisp, high contrast views of the planets. One area where the refractor will score is the ‘cool down’ time is much shorter, if the instrument has to be brought from a relatively warm environment into a cool one, for use.