I'll second Jeremy's sentiments. Being an "expert" is about furthering knowledge about the animals we keep and the environment we keep them in. Selling magic potions with secret ingrediants that make utterly preposterous claims that would be laughed at by a first year biochemistry student does absolutely nothing to further knowledge. In this regard it's actively detrimental; claims of "I don't know how it works, but it works!" (used by one manufacturer) or "We can't explain what it does other then to say it's magic!" (used by another manufacturer) are attempts to get you to buy a product without even trying to find answers.
To be honest, even if a product like Coral+Vital worked documented miracles I still wouldn't use it as long as it's ingrediants remain secret. We stress so much keeping the water in our systems as pristine and 'natural' as possible; hence RO systems, protein skimmers and an array of test kits. Why on earth, then, would someone want to add something with unknown contents blithely to their tank, taking on trust that what it contains not only actually works, but isn't actively harmful? Some of the commercial additives out there actually increase nitrate levels measurably; the manufacturer's claim that this isn't true, that the tests give a false reading when their product is used. But without knowing what the ingrediants are, it's flatly impossible to verify that these claims are true.
As to whom I consider more knowledgeable then myself, it's a long list, composed of folks who's work has served to further my understanding of the hobby. Shimek, Bingman, Borneman, Tullock, Moe, etc etc etc etc ad naseum. Which is not to say that I neccessarily agree with everything everyone of these gentlemen has said. But even when I disagree, it's obvious that these folks have a solid reason for believing as they do, which they are willing to actually explain. I've yet to see Marc Weiss, for example, provide a detailed analysis of why his products do what he claims they do, by what mechanisms they operate, and on what principles they are based.
