schmidt and maksutov cass

 there is discussion from Cloudynights

For lunar/planet viewing, I would choose the C11. In most locations, the usual mediocre or poor seeing compromises scopes above 6-inches or so. Combine the seeing with objects that are not always positioned perfectly high in the sky and both of these scopes will be affected. The Mak might produce a very slightly sharper image compared to the C11. The C11 will produce a brighter image and will have more resolving power when the conditions are good.

The C11 will be better for deep-sky viewing and imaging. There is a comparison here on CN between a high-end, 9-inch Mak and a C11. The C11 came close in most observations so it should deliver better performance against a commercially produced 7-inch Mak. (meaning C8 is inferior to a Mak7?) 

Things to consider for best performance: Collimation, Thermal Management, Dew/light shield (some of the best nights are moisture heavy), A good aftermarket focuser, a good aftermarket high-end diagonal, good eyepieces and a sturdy mount and tripod that minimize vibration.

Mak might not be the most popular CAT telescope, but definitely qualified for planetary imaging

There is actually no competition between these 2 leagues. The skywatcher mak are 2700 mm focal length and below, and prices are lower.

The only competition are the Skywatcher Mak 127 and Celestron C5(150mm aperture), with similar focal length (1500 vs 1250mm)and price(USD 435 vs USD 460).

see astrobinp

another CN thread.   

scopeviews

ioptron Rumak review

ian morison on mak survey

hkastroforum  

spot diagram of Gregorian maksutov

Test from lunatico: planets, Mak (skymax 180) is slightly better than SCT( edge hd 11)