We had ours sold to Greentree. The only frustration I have is that BOA automatically processed any overage to our principle, and Greentree puts it into a separate "unallocated" account that we have to go to them to specify where it goes. Oh, and they harassed us for months regarding refinancing with them, but we just shredded their offers and deleted their messages.

Mortgages being sold is very common. Our mortgage was sold several times - we made our payments on time, to the payment center - never had problems.