I have a 12-19-25 in a Betax shutter. I shoot primarily at 12 and 19 inches with an orange filter when converted to 19 inches. At contact print size I think you will be surprised and pleased at the quality of the images it can produce at all focal lengths.
I performed the Fred Picker "tree braches at infinity test" using a telephone wire and it is sharp as a tack at 19 inches focal length. There is a construction crane in the image and you can count the spars in the boom. That's sharp enough for me any way.
They are heavy, but no more so than 3 lenses, probably less. Plus you have one shutter to deal with for accuracy. Speaking of shutters the Betax 5shutters are a bit funky so don't expect a high shutter speed of much more than 1/25 of a second. Speed isn't a problem at f32 or greater with a filter anyway. At and below 1/25 the speeds tested right on after a CLA.
They have plenty of coverage for back tilt and front rise but front tilt can be a bit problematic. The lens mounts are a bit long and can lead to vignetting in some instances. As luck would have it I never use front tilt so it's not a problem for me.
All in all I think they may be a bit under appreciated for what they are, which is affordable. Can't speak to color, don't shoot it. Flare isn't a problem, I avoid it.
Hope that helps.