There are definitely some drawbacks here. You know what groups and individuals have access, but there is no way within SQL Server who are members of a Windows group. I believe that there are some PowerShell scripts/modules out there that get that information. Here's a link to a blog post that includes session information from a SQLSaturday session that included getting permissions using PowerShell.
Jack Corbett
Consultant - Straight Path Solutions
Check out these links on how to get faster and more accurate answers:
Forum Etiquette: How to post data/code on a forum to get the best help
Need an Answer? Actually, No ... You Need a Question