I asked someone at the HFS for a probiotic and took it for nearly 3 months this summer and didn't notice anything. Just last week I started taking BIO-K+ and already I can tell it's doing something. I'm not sure if it will be a positive change yet, as my stomach just feels different and rumbly (which they say is normal when starting a probiotic). I decided on this one based on someone on this board who is currently taking it. I find the HFS people helpful sometimes, but sometimes they're just going on 'what they're told' and not 'what they have had success with'.
I'll let you know how I do with this BIO-K+ refrigerated soy yogurt, and if you're interested, the one I tried that didn't work was BIO-K+ non-refrigerated capsules.