I haven't tried the kefir, but I will try to track some down.
Recently I started eating Wallaby organic yogurt from whole foods. It says 'creamy Australian style'. I haven't been to Australia, but I do love the yogurt in Europe, much less sweet than the typical US yogurt. I like the Wallaby because its much lower in sugar than all the other brands I saw, and the sugar is in the form of organic evaporated cane juice. It does have a thinner texture than something like yoplait, probably not as thin as the kefir.
The best part about going up hills is riding back down!