I've tried Red Mango, Melon, and Chocolate peanut butter so far and I haven't been disappointed! The flavours are good, service is fast, size is convenient (I always get small.) I just wish they offered all drinks in the small size instead of just the classic ones.
It's a great alternative to coffee/hot chocolate in the morning. I start around 10 every morning and since I don't like to eat breakfast, this is a nice way to make sure I do have something in my stomach before work.
It is expensive (5.34$ small with tax) but I'm told they should be getting MYT Rewards soon so that should help and I know some other chains have a punch card option.