Bumping this thread because I recently noticed a Top Tier sign on a Costco gas pump as I was filling my car. This may be old news to some (and it's not something that's terribly important to me), but I know many here care about this sort of thing and I've seen Costco gas bashed on this and other forums as being somehow inferior. I've used it almost exclusively for about ten years and never had a problem, but for those that are reassured by labels, Costco gas is not only cheap, it's got the right sticky! (At least in Calif.)
