1.... manifold known as a "home run" system

2...Wirsbo system which utilizes 3/4" trunk lines to smaller manifolds that
I assume are located close to
the areas they will supply,branching off into 1/2" or 3/8" tubing to
supply the end fixture.

Does anybody have experience w/ these systems, ?

Have #1 PEX system in our current house except the manifold is copper and
doesnt have the shut off valves on each run. We have stops in the various
cupboards for each fixture. We have one 50 gal Water heater, The pipe is
all 1/2" pex, it works fine..can't say I have any complaints.

We had the #2 system in our former house in AZ. The home was 120' "long"
and had some LONG plumbing runs. The plumber that put the system in had a
lot of experience with Wirsbo pex and recommended it highly. We had a 1
1/4" service after a 3/4" meter. From the 1 1/4, it dropped to 1' pex,then
3/4 then 1/2.
NO 3/8 pex, a few of the risers to the faucets were 3/8 though. That system
worked great too. We had TWO 40 gal water heaters, I can't say one system
seemed any better (or worse) than the other.

I'd either system again.