One easy way to tell ABS and PVC apart is that ABS is black and PVC is white. But since pipes aren’t meant to be seen, plumbers are usually more interested in other qualities.
PVC is more flexible than ABS, but ABS is stronger and more shock resistant. ABS is better at handling severely cold temperatures, but it can warp with exposure to direct sunlight. PVC is thought to be better at muffling the sound of running water.