Plastic repair has come a long way, and a skilled technician can use nitrogen welding to fuse the material back together at a molecular level. This is much stronger than using glues or epoxies that can crack over time. The real challenge is the paint, because bumpers flex a lot, so the paint needs a special flexing agent mixed in. If the shop doesn't use these additives, the paint will eventually spiderweb and flake off when the plastic expands in the heat. Make sure they also check the calibration of your parking sensors after the work is done. If the filler is too thick over the sensor area, it might stop working entirely.