Review their portfolio and don't work for someone you wouldn't hire. You might find things you don't like. That isn't the issue.
Consistency is the issue.
The editing better be consistent within a book and across the document set. Ask if they have a style guide. Responsibilities and Expectations Please describe the duties of the job. That often helps you get a sense of the management style, how much teamwork and independent work is involved, the stress level in the office, etc. Compare this to the type of product they produce.