There are many different styles of Tai Chi like Yang, Chen, Sun, Wu, Hao, CMC, and others. You will learn primarily the AGar-Hutton variant of Yang style with, for advanced students, some Sun style too. All the different styles of Tai Chi are interesting and worthwhile and if you want more information about the differences, please ask me.
The best style is the one you are learning. All are good, but it is the practice of Tai Chi that leads to the benefits. Think, if you will, of all the differnt makes of cars 'Ford', 'Volvo', 'BMW' etc... all have their differences but all of them will drive you from 'A' to 'B'.