We take Bio-Kult and it seems "potent" to me. I thought I could handle larger increases with it since I consume so much fermented food/beverages, but it was too much for me. I had to slow it down and only increase by like an eighth of a capsule at a time. This isn't really a scientific way to determine how good it is, but I noticed with other probiotics I tried, I could start with a full dose with no problem. Definitely do not do that with Bio-Kult! (You're supposed to start with a small amount then slowly increase it to a full dose.)
I buy mine from Blue Herbs. http://www.blueherbs.com/ You get 10% off if you keep ordering through them and the shipping is free and fast.
Follow Mothering