Unsupported face tech is reliable for good ball speeds for sure, I had ap1 forged heads back in the day with under cut face design and ball speed was close enough to p790s, loft for loft, to bridge that gap between players and ball speed irons.
Funny thing about the Mizuno Pro branding, when it was JDM only, I kind of coveted it, now that it's here, I don't know if I love it...