I owned the Orion imaging version (made by SW). I liked it, but in the end, it was NOT for me since I do not have a permanent observing site or observatory. The limiting factor to me was weight - it is 11kg "dry" OTA, and rather awkward to move around as it is decidedly front heavy with that THICK corrector.
Pros:
- Decent aperture
- reasonably well made
- solid
Neutral:
- optical quality - not perfect, not mushy either. Slightly above average perhaps. I would never call the image pinpoint on velvet, but it was acceptable
Cons:
- heavy and cumbersome, and requires a good mount to swing it
- collimation proves to be annoying, but doable. For imaging, you will want Cats eyes or similar, as a laser is not precise enough for good imaging with these
- cool down is long. The fan helps a lot. I found the image was not stabilised enough for imaging after waiting 3 hours. Visual, fine enough, not imaging
- Dew - you will need a dew shield extension and a heater (the combo one will work best). These dew up evilly like an SCT
- Focuser needs replacement - Moonlite makes a flange and focuser that is ideal for it, as does FT I believe.
The claim is it is effectively a 7" refractor - no, it isn't. factor in the central obstruction, and you are down to a 5" refractor, with optics on par with say a SW 120ED. And NOT being ELISTIST, the image will NOT be as good as your TSA 120. Several interferometric testing reports have shown it falls short of the TSA120.
If you were to consider the Intes version (which SW copied almost EXACTLY), which is decidedly more expensive unfortunately, you will get a MN with superior optics to the SW/Orion, and a better stock focuser.
I liked the Orion MN190, but in my experience the cons outweighed the pros. Your circumstances are different, so many of my cons won't be a consideration. The killer in the end for me was the cooldown (though Glend says his cooldown is less - maybe he is talking visual only?) and the optical quality, which in my exact case was inferior to the Vixen FL102S I had.