I liked and admired Lost from the beginning, didn't miss very many episodes, watched a number of them twice, and was very happy with the ending. I think the people who denigrated the show either weren't willing to try figuring it out, couldn't remember what went before and thus missed the significance of the payoffs, or simply prefer to watch shows that don't require any viewer involvement.
They answered every question for me except one. If Hurley was the protector of the island at the end of the island sequences, why was Ben the one who evidently didn't die (everyone in the church was supposed to have died), and was left outside? Or did I miss seeing him enter the church after all?