Let's look at each of these to help you decide what might be best for you. Attorneys Attorneys should not be lumped together as equally good or bad.
Attorneys are individuals and come with the strengths and weaknesses of any group.
Probably the best indicators of attorney competence are the attorney's experience and good personal recommendations. Be careful in selection since these do not guarantee success or ability. They may have occurred years ago, and examinations may not have been designed to test competence. They certainly do not test immigration law knowledge to any extent. This writer is not familiar with the exam and cannot comment on the certificate as an indicator of competence.