A friend of mine who was in Washington.
When he started to research which attoney is good, he got very kindly many answers from different offices.
But when he picked up one, even the price is 3 times higher than other offices, he believed it must be the best one in washington.
But after he paid the deposit, he waited 30 days , and never had any information from there. He called, but only can left message. he went to that office many times, that attoney's face had been changed total different from the beginning.
His case was total failed. it took almost a year, and the letters from immigration office to attoney, were asking documents, additional information and so on, that attoney never did ,even SSN was wrong.
So, I suggest you better ask find the attoney who has a very good reputation. you do not have time and money to try one and another one.