Red Mango/Tartini/Yogurtland in Cupertino
Red Mango (on Rodrigues x Torre) opened just around the corner from Tartini (on Stevens Creek x De Anza), and while it has a much smaller selection of yogurt and toppings, it does have cute, soft, little mochi balls as an option! $3.95 for a small portion (you don't get to serve yourself as you would at the other two shops); the service is friendly, and the yogurt is a bit smoother than Tartini's. Tartini has a better fruit topping selection.
My teenager prefers Yogurtland (behind Elephant Bar on Stevens Creek) because it has chocolate (too sweet for me) and other sweeter flavors. It has the largest selection of yogurt flavors and toppings, and while it seems to be the yogurt of choice for the teen set, I found the quality comparable to RM and Tartini. It was fun doing the taste test, and they were all worth a visit.
20560 Town Center Lane, Cupertino, CA
19700 Stevens Creek Blvd, Cupertino, CA 95014
I love Yogurt Works! It just started serving Lychee, which Tartini suspended. There's a wide selection of sweet and tart flavors.
Coolicious is open, near St. John's and FedEx on Lawrence. Small selection of flavors and toppings, and you can't serve yourself, but they also have great gelato.
I am a big fan of Yogurtland over the others - I enjoy the self-serve aspect so I can try a little bit of everything.
I prefer Yogurtland because of the self-serve feature and the availability of sugarless varieties.