I believe I test rode the Aluminum and the Pro, and for me the
shallower
head tube angle on the Pro was more comfortable.

I like to stand up and climb hills and lean quite a bit forward when I
do and the
72 vs 73 felt more stable to me.

I think the head tube angle may be one of those things where they
shift it o 73 or more and it's not best for a lot of people but a lot
of ppl don't know because there's hardly anything else on the market
anymore.