Rear Bumper fillers - ABS plastic or Fiberglass

[REGALTURBO]

In the process of a body off resto. Always used originals but these ones are too far gone. Looking for opinions. Has anyone used either and just wondering about how they fit and hold up.
Thanks.

 

[NEVER ENOUGH]

I went with glass f&r. With a little tweaking they fit great. And look great.
I would use them again.

 

[HOT ROD-GN]

Fiber glass is the way to go..