I use OSC for a few reasons:
1. I am time limited. I don't have the time to put 30-40 hours into one subject. 10-15 yes.
2. CMOS is what the future is going to be. CCD is a dying technology. So I went that way rather than have to switch things up later. There are mono CMOS I believe too.
3. I am willing to sacrifice a little bit of 'quality' for the simplification and time savings
4. I use the QHY367 on my fsq106 and it fits the image circle great. Not many CCD, if any, would economically do that like the 367.
5. I do Hubble with this camera and they look very good.
If I were retired and had all the time in the world, or had a job where I was home every night, I might do the mono. But the image quality with this camera is very good so I don't see the need to worry about mono at the present time.