I've owned both, but I didn't have them at the same time. They both use R2S pearl for the cover, but the Hyroad Pearl has the Inverted Fe2 core while the Punch Out has the Turbine. The Hyroad's core numbers are 2.57 and 0.046 while the Punch Out is 2.55 and 0.038. Basically, all things being equal, that would mean you'd see a bit more push and a bit stronger recovery out of the Hyroad as opposed to the Punch Out. For what it's worth, that is basically how the two have compared for me. I wasn't a big fan of my Hyroad Pearl. I felt it was too long and too late for me and my game 99% of the time. Now, maybe I just wanted to use it more frequently than conditions allowed. My Punch out is just a bit earlier (still very clean up front) and is still plenty strong off the spot. I actually considered going to it yesterday at a tournament that forced me way inside, but I still liked the read of my IQ Fusion better.
In any case, to answer your original question, although you could certainly enhance their differences by drilling/prepping them differently, I still think your original thought was correct; I think there is probably too much overlap to have both unless you bag a very, very specific arsenal.
