Gentlemen,

Long before the world of CAD was even around I was punching cards for programs such as Mare Island and Dynaflex these programs used +Y as up!

How and why CAD programmers chose +Z as up beats me but I am willing to bet they probably thought it was the way to go at the time.

ANSI for pumps uses a different axis set up, and others as well... I am sure each group had their reasons at the time.

Just be thankful that automobiles are quasi-standard devices... steering wheels and pedal controls, but some people drive on one side of the road and others the other side....

Which one is better or right? Both!