The difference is, you can dial it back as appropriate with the KB unit, or the Jacobs one if you could ever find one.
What size fuel lines are you running? 24V will have that thing humming along pretty quickly. I would be worried about the pump overheating, possibly pressure creep if the regulator/return lines aren't up to it. I don't know anyone running 24V to anything but a starter motor.
I'm also not sure I'd trust a $38 Chinese regulator from a reliability standpoint, but then again, I usually have to drive pretty far to race, and when something craps out, I'm usually done for the weekend + $350 entry fee!