Non-dairy probiotic drinks

Does anyone here have experience with non-dairy probiotic beverages?

I'm a big fan of kefir, but I've been trying to cut down on my dairy intake. Last night I stumbled on GoodBelly, a fruit-based probiotic drink, on sale at Whole Foods. I ended up buying the cranberry-watermelon flavor and had about half a cup at breakfast this morning. It tasted pretty good, like one of those flavored water drinks, more watermelon than cranberry, not as sweet as regular juice (though it has more sugar than kefir). It did have a very, very brief almost after taste that wasn't so good--I suppose the after taste was a kind of oat-y sour (but my description is likely influenced by the fact that I had read the ingredient list, which includes, besides the 25% fruit juice, cultured oat flour and barley malt). The sugar is high, and the calcium is low, but GoodBelly otherwise has decent nutritional values--vitamins C, A, E...

Anyone else have experience with GoodBelly or drinks like it? Have folks who've found kefir helpful with digestion seen comparable effects with the non-dairy drinks?

GT's Kombucha (also available at Whole Foods) supposedly has some probiotic qualities and aids in digestion.

I just had a bottle of the Kombucha from Hannah's Bretzel (priced about $4/16oz. bottle). It was... okay. Seeing sediment on the bottom, I gave the bottle a good shake -- something which, upon closer inspection, the bottle said expressly not to do (oops!). This may have resulted in a slightly carbonated beverage that was less than pleasant. I went with the original flavor, and there were maybe 3-4 others available, as well. Overall, it tasted a bit like sour tea. Not very assertive and hardly sweet, not necessarily in a bad way. It just had an odd mouthfeel (again, possibly my own fault). I'm not sure that I'll be in a rush to try it again (certainly not at that price point). FWIW, there was also a note saying that there would be some alcohol in the beverage from the fermentation, clocking in at an ABV of 0.5% (important to know for those that can't drink alcohol).