Alot of cpvc in houses around here. I have it in the house I'm in now, and no complaints. As to the sagging, I don't think it will perform much better that pex. Never heard anyone complain about odor or taste caused by their pipes (except iron), but have heard many caused by the water. I'm not a plumber, but I do quite a bit of it occasionally, and I pretty much only use pex, and have had no complaints. Imo if its installed and attached properly there shouldn't be any problems. If in doubt use a compressor to blow the lines, or a shop vac to suck them dry. I have also heard there is a new pex that won't bust when frozen, but I haven't looked into it, may just be a rumor.