I have red-green color blindness, so it's a problem. Dark red on black is bad, green with yellow or brown is bad, shades of blue and purple can be hard to distinguish. Yellow on black good, bright red on light background good.
Do many of them have the option to change the colours?
Yeah, it seems like most editors now it's not that hard to customize the settings--so I end up futzing around with the colors every now and then to see if I can come up with something better. It remains a not very satisfactorily solved problem.