Considerations in Using the EAD
Put simply, generally, it is safer to maintain a nonimmigrant status rather than relying solely on the I-485 and EAD. However, there are valid reasons that many decide to take the calculated risk. For some, there is no choice, as the employer will not extend the H1B status after the person has the EAD. Still others may have faced layoffs and other job issues, and have had to move to a new employer using the EAD.
For many, it is a choice and a balancing of risks. Once the I-485 has been pending for 180 days, applicants often start to consider job changes under the American Competitiveness in the 21st Century Act (AC21). All employers in the United States must accept EAD holders; employers are not required to sponsor H1Bs or other nonimmigrant categories. So, the universe of potential employers increases once one has an EAD.
This often leads to choosing between working on the EAD on one side and passing up possible career-advancing opportunities to keep non-immigrant status on the other. For that reason, many people ultimately decide to work on the EAD at some point.
When weighing the choices, it is a good idea to try to assess whether there are any enhanced risk factors in the applicant's I-485 case. While all cases have potential weaknesses, some cases are more likely to run into problems than others. It helps to talk to experienced attorneys (Murthy, Immi, etc) who can give a better assessment based on your background and knowledge of current trends.