I have been asked more than a few times on the forums in PMs about which is a better driver I spent about 40 minutes with the two of them switching back and forth and giving them a true hard core simulator session.
ISO-T 9.5 Xcaliber Superlite55 S tipped an inch…. KE4 TC set at 9.5 Xcaliber TSL TS tipped an inch. The TSL is a sub 50 gram shaft both have a 4 gram weight in the sole.
The ISO-T threw up a 284 carry 296 overall, 18.7° of launch 167 mph ball speed and 3066 spin.
I immediately picked up the KE4 and put up 286 carry 298 overall, 18.1° of launch 168 mph ball speed and 3035 spin.
All session long these two were this close. The ISO-T has a bit of a fade bias. The KE4 I can turn over in a slight draw fairly easy. They feel quite different and and I will game either one this year. It may even come down to course layout on which one I chose.
For a ball speed reference I have not found a driver than can eclipse the KE4 yet. 4 different OEMs so far.
As for forgiveness I might give the KE4 the advantage. I have yet to hit it outside but it’s a stud on the simulator. Feel wise I’m still with the ISO-T.