STi = killed/blunted leading edge AND more bounce overall.
TS1/2 = rounded leading edge, trailing edge (rocker sole), not much.bounce. TS1 narrowest sole followed closely by TS2. Leading edge sits pretty close to the ground.
STi2 = rounded leading edge, trailing edge, even more so they the TS2. Sits right on the ground. Not much bounce per spec. Wider sole then all but not by much.
XV Pro more bounce a little relief on leading edge but not much.
All a bit different. But those rocker soles really work well with my steep swing.and get through the turf. The TSi2 has a LOT of sole relief. Flip it upside down and look/compar vs. other irons. Almost too much relief. I'd give the slight edge to the TS2, they were amazing. STi2 worked but in ould still take a healthy divot. enough with the killed.leading edge and more bounce.to be serviceable. XV Pro, just enough bounce and a smidge of round on the leading edge to make it serviceable. I forget sole width on them but close to all the others. Played for al.kst a year and they are a solid iron.