Tested this one against my KE4 tour + both with a program 130 6.0 shaft. Forgiveness in a big way goes to the STI OS. Feel goes to the KE4 tour. Launch was pretty close to the same, for me the KE4 tour might’ve been a little higher flight (probably due to the lofts of the other clubs being stronger).
Bottom line the STI OS could go in the bag tomorrow. I’m gonna continue to hit them both. I may pick up a PW head of the STI OS as well, just to thoroughly test! Lol