That's fine, but I disagree. To me Hayley is a lot trendier. And popularity does matter to me. Hayley is in the top 20 when you combine spellings, Hadley doesn't even make the top 100. A name outside the top 100 can hardly be called common. It might get common but it isn't yet. Trendy, maybe, but as I said I find it a lot less trendy than Hayley.