Light and compact construction but long focal length. Little levering effect because the heavy parts are close together. Mirror telescope without any obstruction. Due to the tilted construction it's hard to find an object without a Telrad or a finder scope. High magnifications without the use of ultrashort focal length eyepieces or Barlow lenses.
Low magnifications are only possible with a small field of view.
Image qualtiy is close to the one of three times more expensive apochromatic refractors with the same aperture. It's up to you to decide which of these points are relevant or irrelevant advantages and disadvantages of the Kutter-Schiefspiegler system. It's an ideal telescope for observing the Sun, Moon and planets. The system provides a magnification range from 56 up to 300 times. The 90mm Kutter is a handy telescope with a carrying handle attached to the central unit.