One big difference is the addition of a new four-model structure with Tour (T) Players (P) Extreme Forgiveness (XF) and Super Game Improvement (SGI) now offered. But the real design difference has to do with the a new material used in the clubs that produces more speed and distance among other things.
The newest iteration of the Srixon Soft Feel ($19.99/dozen) golf ball is a two-piece model aimed at players looking for straight distance with a very soft feel at impact.
Since then Thomas upgraded to the new Titleist TS3 driver and a TS3 fairway wood. Those two clubs have not be unveiled to the public officially yet. You can expect the company to announce them later in the year.