My experience with GW letters has been split. Only submitted 2 with the first being for lates on a store card and received an e-mail back within just a few days that the TL would be removed from reporting, but that I still had the ability to use the card - even received a $1k CLI on it within about 6 months. The second one was for late mortgage payments and I waited about a month before hearing that the record was accurate and they had to report it. Luckily, that falls off in Sep/Oct of this year, so wasn't too worried about it.
Just received a call from someone at the BofA EO and the gentleman who called me was very nice and said that it was just a call stating that they received my letter and will be researching my account and will have an answer for me by the end of the week!!! 
Keep us posted!
and I agree, the wait is brutal!
Starting Score: 602 (03/08/14)I got a letter from BofA saying they are going to change the status of my accounts to Paid/Never late and a $0 balance!!!!!!! My first success with a goodwill letter!!!!!! So excited!!! Totally made my day!!!!
That's totally awesome. So far, I've had little success on GoodWills about payment status, even though I have a very good case for doing so. Glad to hear a success story. Gives me some hope!