I thank everyone for their input. I realize this may not be the most interesting topic.
I don't really need two-tone prints, although if it's an advantage, sure. Back-up is defiantly a good advantage, yes.
What im interested in is the print quality/detail in using 2x extruders , one extruder having a smaller exit diameter than the other for 'detail'. I need to print things like adapters and couplings to join multiple carbon fiber tubes into 1 node. Also i'm going to attempt to print housings for EDF's (electronic ducted fan), and thrust tubes. These are obviously on a small scale for sUAS, small unmanned system. They won't have any flame component and not much heat either except maybe some radiant heat from large brush-less motors.
Has anyone handled or tested ColorFabb's XT CF20 ? I'm interested to see how well it runs through printers...etc.