The difference is knowing that some products have trials and reports to back them and some products don't. Soltron owns a series of trials carried out both overseas and locally which is why it is endorsed by CEYPETCO. Pay attention to the marketing gimmicks. NO fuel treatment can ever save fuel up to 50%. If a product is free from chemicals (eco friendly) with no side effects, backed by sufficient R&D to prove its benefits, endorsed by a government body and doesn't oversell itself, I consider it to be a pretty legit product.
