I'm an ex-electrician / commercial architect building my own house. I know a bunch of residential but commercial is definitely my forte. I specified cast for the vertical stacks, but the other day my plumber offers me a choice between PVC and ABS for all of the other runs. In all of my personal home renovation I've only seen ABS and didn't know PVC was an option. My plumber says it doesn't act like a noodle when it is in the sun for a while and is quieter than ABS. Could I get some opinions and info so I can make an informed decision, please? I'm not worried about parts availability... the big orange box doesn't carry PVC, but there are numerous plumbing supply houses around. Thanks!!!