Great flavor variety, convenient location and it's healthy (I hope)!
They have really tasty drinks and usually a few seasonal/special flavors. It's a friendly atmosphere and the place is always clean. Employees are helpful and usually offer their opinion on a flavor if you so desire. I have tried many of the flavor varieties and usually prefer one with mango or passionfruit or both!
I'm also a fan of the peanut butter/chocolate smoothie and the pretzels.