I worked with Chen immigration firm for my I-140 NIW/EB2. From the first day, the firm was detail-oriented and provided me with a timeline for the whole process, and papers and other documents needed. They evaluated my case before starting and made decisions after which we started the process. In general, they are very organized, respond to my questions and emails promptly and thoroughly, and did a very good job collecting and compiling evidence and providing samples of LoR for referees. The whole process went smoothly and I got approval in 9 months, from the day we submitted the case to USCIS.