Why is the water pressure in my home clearly less than my neighbors?
Look for something like this.

near or on the water meter.  This is a pressure reducing valve, and it's used by some municipalities to control the pressure entering to house.  They are adjustable, so the one in your house might be set too low.
If you have a manifold setup on the PEX system, check to make sure the shutoffs on the manifold are fully open. You can also check the main shutoff for the house, to make sure it is fully open.
If you still cannot get better pressure, you might try calling the municipality and asking them for help. It could be a problem with the system before it enters your home.
This answer assumes you are using city water, if you use well or another water source there may be more things to check.