I have no opinion on the JS pex...yet. I will be in discussion next week or the week after with a rep for them. I will say that if you are not on a recirculation line, then you would be absolutely fine to use the Uponor pipe and fittings. If you are on a recirc line then you may want to use the Zurn pex B pipe and either the Zurn expansion fittings or the Uponor expansion fittings. Not all Ferguson counter people know about the Zurn expansion. No reason to carry both Uponor and Zurn expansion, especially now that they have the JS expansion, by the way Ferguson owns Jones Stephens and is the largest plumbing supplier in the United states. so they will back up any warranty no problem if it ever happens.