Given the fact that I used to work there, now that I know the behind-the-scenes of the BBT making, I know why people keep coming back.
For the slushies, they use fresh fruits, and they have a huge selection of them. You can always ask them if they can make a particular Asian drink (i.e. "red bean ice"), they'll tell you they'd try, and voila! A new drink just for you. The people there are always friendly and extremely efficient. Definitely worth your time.