It's funny that none of the replies here seriously address the issue of happiness in arranged vs. non-arranged marriage face-on. I'm inclined to believe that there is an inherent bias against arranged marriage to begin with and so certain angles of reasoning are simply not considered.
I will say, very frankly, that I believe arranged marriages have the ability to make marriages, on average, more happy. Before any of the free-choice fanatics decry this, here is why that does not work here: happiness is purely perception. If you change the parameters of the environment, the equation for happiness does not remain the same, as in, more freedom does NOT imply more happiness as many people would like to believe.
If you are starving, anything edible tastes good. If you are a slave since birth, any reward is enjoyable. If you are resigned to an arranged marriage, you are less aware of the pains of opportunity costs, therefore it is very plausible that you try to make the best of the marriage.