Let's see... I've tried everything except VSL3!
Custom Probiotics, along with countless other probiotics I tried, did nothing for me sad to say, waste of a lot of money.
Water kefir did nothing for me.
Raw milk kefir from the grains and also from the Body Ecology powder was most helpful for me at several glasses per day - I feel best on this or high dose probiotics everyday. I like to eat 24 hr yogurt but it wasn't as helpful as kefir.
DS couldn't tolerate ferments or food probiotics at all - rashes and insomnia.
DS needed bifidobacteria hands down. He tended toward loose and really smelly stools. It wasn't until we finally tried Natren Life Start, and then Pharmax Neonate that both issues went away that taking all his food triggers out hadn't done. He was intolerant (not IgE) to dairy (which is why I took out the Natren) but he tolerated the lactose in Neonate just fine. It is recommended for dairy intolerant kiddos, I just wouldn't do IgE level. We moved onto Mindlinx, on which he lost his dairy intolerance. That one, and all other Pharmax, is completely dairy free. We also use the Pharmax Intensive capsules which do not have FOS. They are over 30 billion (more than stated label at time of manufacture) I think and never gone up more than one/day except when I had a stomach bug and several per day took care of it very quickly, that's the most I've ever done.
High dose probiotics were the first step in helping me get rid of hay fever and my interstitial cystitis (which I wonder how much is a ph thing too? or gut flora metabolites?). I also like how probiotics are calming and you hardly have to use toilet paper at all.