Meaningful comparisons of multis are probably impossible, but if you're concerned about impurities and quality control, Centrum would be a great choice. A patient of mine is a quality control chemist at Wyeth, recently purchased by Pfizer, where it's made. He tells me what they go through to assure purity and quality there, and it's really impressive. They're constantly checking and rechecking absolutely everything. People like to rag on "Big Pharma" here but Big Pharma clearly has the money and resources to make a pure, high quality product.