My preference is for Life Extension Foundation. Large org with a mission beyond money.
For general manufacturers, I go with Now Foods, a large and US based company. LEF carries some of their stuff.
It's plausible that LEF would care more about their reputation (and perhaps about their customers) than some random company which is selling through the big chains. Still, I'd like to know whether you've got a line of thought which is a little closer to the supplements themselves. For example, does taking the supplements produce effects which are a good match for what the supplements are supposed to do?
A friend of mine told me she got very good results from Vitamin World melatonin, and little or no effect from Natrol melatonin, and that reminded me of recent news that many herbal supplements don't have any herbal content.
Does anyone have information, whether based in personal experience or from studies, about which brands are more reliable about their contents?