Like everything else you pays your money and takes what you get for it. Vermeil varies in quality. Some vermeil cannot even be sold in Europe as it has a layer of nickel. As Katbran says, quality varies, with some having a very thin layer of gold.
Good quality vermeil will last well - I have vermeil clasp on my own items which get a lot of wear and are fine after five + years. From my viewpoint here in the UK vermeil is all precious metal too while gold filled might be more gold by % but cannot be assayed and hallmarked.