There is only one way to find out. You have to give it a try. You can read all the manufactuers scientific methods (or BS) on why their's is the best. It won't tell you a darn thing on how it sounds. To think that some people actually swallow this garbage without trying, has no credibility with me. There are some tweaks that will give more importance in sound than a piece of gear. Yes, there are some snake oil products. Some you have mentioned will work for some. Others will tell you that this is snake oil. please do not underestimate the importance of certain racks, shelves, outlets, room, PCs, and dedicated lines. Only you can determine what is snake oil and what works.