The servicing on my mortgage was transferred to Nationstar Mortgage a couple of months before the loan was paid off in the course of a refinance. I was only with them for a couple of months but their routine customer service was great, very friendly and helpful during the transfer as well as getting the docs I needed in preparation for the refi. (In particular, the phone reps were generally very helpful. The secure e-mails via the website were not answered promptly and I wouldn't suggest using this method unless matter wasn't urgent, or you were specifically attempting to establish a paper trail.)
Dealing with the intricacies of the mortgage payoff was a different story. Nothing egregious took place but Nationstar didn't shine here: a lot of incompetence on their part, they wouldn't process the payoff until I wired in extra funds to cover an escrow payment they made at the last minute, and didn't bother informing me of that fact. I ended up paying a few extra days' interest and they actually charged me a late fee for the month since they held the payoff funds in suspense past the 15th (which I am still attempting to contest almost 5 months later... ). At one point the customer service reps told me that there was no department that dealt with payoffs ... and I'm inclined to believe it based on how disorganized things were! Still, Nationstar got the main things right: they recorded a "Satisfaction of Mortgage" document in a timely fashion and reported the account as paid in full.
(Same story with the intricacies of credit reporting. For some reason they reported my account to the credit bureaus with the notation, "dispute resolved by grantor". It persisted with TransUnion even after I asked them to delete it, so I had to put in a few requests to Nationstar to delete the notation. I don't know whether they ever figured out what I was talking about or not, but it eventually disappeared from my TransUnion report. I did see it again on Credit Karma recently although that might just be Credit Karma...)
Short version: friendly customer service in the course of ordinary business, a bit thin on professionalism and expertise when it came to the specialized stuff.
