Do or DONT fiberglass body parts

I don't own any fiberglass parts currently but I do plan on getting some in the future so I can't speak from real experience, but the general consensus I seem to get from online reading is that A: you get what you pay for. B: No matter what, you will have to do some custom fitting for your particular car. C. In general if your car lives outside then you should probably stay with steel, and if your car sleeps indoors then the fiberglass should last you a long time.