There are differences however including most notably more adjustability in the form of Titleist’s SureFit CG technology that allows for more specific spin rate and launch angle tuning. The TS3 also features a more traditional pear shape and tends to produce more of a mid-launch as compared to the TS2’s higher launch.
Since then however the JPX 900 models most notable the Forged Tour have been a huge hit with all kinds of players including two-time US Open champ Brooks Koepka.
Matching putter type to stroke shape isn’t a great fitting strategy. In fact research indicates that how you “release” the putter is much more critical. Bottom line: If the putterface is square to the target line at impact it doesn’t matter what it does during the rest of the stroke. Selecting the correct hosel can make all the difference here.