[chrismorse]

I was a contractor for 35 years and started out doing copper. When PEX came out, it was called "Aqua PEX', which used the expansion tools to enlarge the diameter of the "pipe", with a collar on it - which was then slipped onto a barbed fitting - never had a joint fail, except once on a remodel that was running 100 PSI + water pressure.
Aqua PEX is Pex A which uses the expansion tool with a sleeve over the pipe. PEX B, i have no experience with, but i can tell you the parts are not interchangeable - the "B" has a smaller inside diameter and uses a proprietary "Crimp" fitting and tools. My guess is that the B system is a bit faster, because fastening goes more quickly and you don't have to wait for the pipe and collar, (Pex A), to shrink back to its original size/seal pressure tight.
We once replumbed an old farm house with the "Manifold" system and it went quite quickly.
Think about for a minute, which system is likely to have more waste : PEX - 50-100 foot roll, or copper with 10-20 foot sticks??

I still use PEX A cheaper parts and a lot less labor.

Fittings, brass, Fiberglass, or SharkBite??? (all PEX A). SharkBite is faster, but more costly - a lot. I've had no failures/leaks with either fiberglass or brass, but i am still a bit old fashioned and sleep better with brass fittings when concealed in a wall or inaccessible part of the structure.

So far, fingers crossed, I've had no rat chew failures, but i have had a few pinhole copper failures and a few joint leaks.

If the Pex is exposed to potential freeze, I still like to use foam pipe wrap to protect the pipe - I've only had one minor PEX pex freeze leak.

The 12 volt Milwaukee Pex expander is a real Jewell, especially when working under the house,, or tight spaces.

Like all plumbing types, (Pex, PVC, CPVC, Copper, Galvanized), i still like to use canvass fitting bags , "Parachute Bags", sorted by type and pipe diameter, 1/2, 3/4, and 1 inch.

Leaky Chris