[Wavytone]

Well...There are several issues.

1. There are several mak variants:

- Maksutov Newtonians, mainly by Intes and Skywatcher; typically f/4 to f/8;
- DD Maksutov's original designs;
- The "Gregory Maksutov" cassgrain with an aluminised spot on the corrector, probably the most common type;
- the Rumak cassegrain, where the secondary mirror is separate from the corrector;
- sub-aperture mak cassegrains (Vixen and Takahashi).

2. The optical characteristics inherent in the design you are considering, and there are several if you include scopes that can only be acquired secondhand.

If looking for a lunar & planetary scope they're typically f/12 - f/15 with small secondaries and this really does count. Intes made some at f/8 and f/10, but like Meade/Celestron SCT's, it is not an optimal choice.

All maks are by design perfectly corrected for spherical and chromatic aberration on axis and if well made, should show textbook diffraction patterns at extremely high power. For example the Rumak gives perfectly corrected images over a flat focal plane (nirvana, some would say), whereas the Gregory Mak designs typically have a slight spherochromatism and a curved focal plane, similar to SCT's.

There is as usual the question of the central obstruction due to the secondary mirror and baffles. This varies. Some of the smaller maks have quite large CO, as high as 35% (eg the 102 and 127mm ones from Skywatcher/Orion).

Some designs have smaller secondaries - mine for example is 26%, and some have secondaries around 20% at which point the image is as good as unobstructed.

3. The quality of the optics.

Some manufacturers were awful, some average and some are consistently very good. Over several decades there have been a few premium maks like mine with very high quality optics which are in class of their own.

The point here is that some - notably Intes, Santel, AP, and TEC - consistently produced exquisite optics and these do command a premium. My Mk91 for example is probably the best thing you could wish for, short of a 9" APO.

Intes guaranteed 1/6 wave for standard scopes, 1/8 wave for the deluxe versions. Excellent if you can find one but heavy, built like a Russian tank - crude mechanically but effective.
Santel likewise 1/8 wave or better and with a DPAC interferogram.
Meade - made a 7" Mak Cass LX200, these are excellent optically if you can find one - however need some surgery - throw the fork in the bin and open up the OTA to remove a massive iron weight in the back;
APM Germany - Intes optics (ie superb) in an OTA built buy Matthias Wirth, small numbers only.
Astro-Physics and TEC - don't know if they set a tolerance but they are consistently excellent and beautifully built.
Skywatcher - early ones (2006-8) OK but not great, but the recent examples I've seen are consistently very good.
Orion (Synta) - same as the Skywatcher ones, rebranded
Saxon - Chinese versions included a 150 and 203mm mak, no idea of quality as I haven't seen one. Rare, it seems.
Ottiche Zen (Italy) - good optically but the correctors are not coated. Handmade in small numbers by a craftsman.
iOptron (made by Bosma) - cheap mass-produced Chinese version. Haven't seen one, personally.
Orion UK - do not touch those with a bargepole.

4. Size, weight, portability.

5. The ultimate is Questar, who build a scope designed as a portable observatory in a shoebox, built to last a lifetime, provide guaranteed support seemingly forever (a Questar made in 1957 can be serviced, cleaned, recoated and updated even now). Much admired, for obvious reasons.

6. Issues.

- the heavy corrector - can dew over but because it it is so thick theres more thermal mass, so this doesn't happen as quickly as it does with an SCT. Options include heaters or dewcaps. I use a dewcap and don't need a heater.

- internal tube current off the baffle - as with SCT's and the options is the same - either cool the scope, or insulate it. Insulation works very effectively on mine - it is usually ready to observe as soon as I am.

- focussing mechanism - some maks have moving-mirror focussing (like SCT's) with the usual issues with mirror slop (Skywatcher). Some use moving mirror focussing but got it right (no slop) - Intes, AP, TEC. Others have fixed mirrors and use a focuser bolted on the back (Santel, APM and some Intes) which means the focussing range is limited.

- collimation. Like all cassegrains they are sensitive to misalignment but f you get it right it should stay that way for a very long time.

7. Why use one.

Try mine on a good night and you will understand.