I'm pretty sure we've scored a ton of goals the last 1.5 year from Alves' crosses. He crosses a lot, so it's given we are going to score from them once in a while. Whether you consider him a good crosser or not, his crosses have turned into some spectacular goals for us. Also you have to accept that most crosses, no matter who it is, don't find a target.
Are there better crossers out there? I'm sure there are, but there are only a very few that are considered to be dangerously consistent, Beckham and Dinho being two of them.