Tasti D Lite actually opened it's doors in NYC in 1987 and has been popular ever since. Pinkberry, a relative newcomer to the scene, began in California in 2005, but has also become extremely popular in NYC.
The similarities between the two are many---both tout a healthier alternative to ice cream. Both are relatively low-calories; a small serving of Tasti D Lite will run you between 70-100 calories, where the same small serving at Pinkberry is 100-140 calories (depending on flavor). They each have a dizzying number of variations and fresh toppings. However, that's where it ends---the flavors are really entirely different.
Tasti D Lite, located in the Staples Plaza (which seems like a poorly selected location, in my opinion), is ice cream made from non-fat milk, so it actually tastes like ice cream, and is surprisingly creamy considering there is less than 3% butterfat (most ice creams have up to 10%). Pinkberry, in a comparably fantastic location right on the Post Road in Fairfield, is actual frozen yogurt with live cultures, and it tastes tangy like yogurt. So, it is really a matter of personal choice---you are either more of an ice cream person or a yogurt person (I won't tell you which I am).
Both have a fairly limited number of actual flavors being swirled (no "31 Flavors" here), but have a lot of topping choices. Tasti D Lite had Chocolate,Vanilla, Red Velvet, and Oreo-Peanut Butter "on tap" as they said, but also has at least a million flavor combinations they will make for you right there (which blends in various toppings and flavored syrups). Pinkberry also had the traditional chocolate and vanilla, plus mango, pomegranate, coconut and pumkin (seasonal). The toppings ranged from freshly cut fruit, toasted nuts, granola, and then more sinful options like chocolate chips and even rainbow sugar cereal. I have to admit that in both shops I was a little overwhelmed with too many choices.
I think because of Pinkberry's great location (right next to Colony Grill) and the media blitz it received, business has been gangbusters. There has been a line out the door every single time I've passed by. The times I've been to Tasti D Lite have been a little off-hours, but it wasn't enjoying the luck as it's downtown competition (but is at least three times the physical size). But, as people get out to try both, I have a feeling people will start showing their allegiances...you either like yogurt or you don't. But if you don't, then you have to be willing to drive a little out of the way if you want that lower-cal alternative to Dairy Queen.
You never can have enough ice cream....so I wish them both the very best of luck!
Learn more about Tracy's Connecticut cooking classes or find her recipes on her Season To Taste blog.