I did everything by myself and my cases were approved smoothly.
Background: Ph.D student on chemistry. Six journal papers but no first anthor.
I-140 was submitted at the end of Sep, 2004.
I-140 approved on April 4, 2005.
My I-485 approved at the beginning of Sep, 2005 and GC received one wee later after I-485 approved.
My wife's I-485 approved on july 11, 2006 and GC received on July 17, 2006.
I got lot of help from here.
Good luck for everyone.