Hi Michael, I can speak a little from both sides of this argument. It all boils down to three things.
1. Time constraints: The OSC gives good results quite quickly you can easily produce a nice pretty pix as you put it in a couple of hours imaging. The mono with filters will add almost double this time taking into account things like capturing each colour separately, stacking and processing but generally speaking the result will be a little better.
2. Budget: A reasonable one shot colour camera can be bought for a couple of thousand dollars, a similar mono will cost at least $1000 dearer then around the $500 -$1500 for a set of filters plus $750 for a filterwheel to match the filters.
3. Processing/ computer skills: The amount of extra computer work to put together a multi colour filtered image is quite a bit. Software gets much more critical and less automated requiring more time, effort and skills.
I have had both and ended up selling my mono camera, filter wheel and filters for many of the above reasons but by far the most critical to me was the time constraints. To achieve what I considered a reasonable image with the Mono camera took me at least a full night or two split nights at a minimum. The OSC produced a reasonable image in half to one full night and in my opinion the results were very much the same in the end.
Dietmar wrote an interesting comparison between similar OSC and mono cameras
HERE which may be of interest.
I hope this helps.