Its like everything if you listed out all the stuff you need to be aware of with a metal frame it would be just as long. I am not an expert in flexibles, I know enough about them that I say lets not do that every time one comes into the conversation. They suck to "patch" they don't last very long, and are typically a wrecking ball for the tissues.
Slightly off topic, what is the general census on these type of frameworks compared to metal. Solid alternative, only for certain situations, or better in every way?
Personally I don't care for them. I cannot get the finish lines perfect like metal, They don't support the teeth like metal, no occlusal rests. The retentive elements are bulky often plaque traps. I "burned" a flexible in my ivobase left a brownish spot. Nothing I could do about it.