Impressive! Plan to spend at least 1.5 hours here. Visitors are granted free admission, but you still have to check in at the front desk in the main lobby. The grounds are beautiful and you get to walk through Billy Graham's childhood house.
Billy Graham is a meaningful figure in my household. I grew up watching the crusades. It was fulfilling to me to walk through the Library and learn about the history of Billy Graham's work and life. It's a museum with a lot of video footage to keep the story going.
Plan to eat lunch here, although if you are on a veggie-only diet, they only offer salads. The main menu is chicken salad or BBQ with sides like potato salad. There is also a well-stocked gift shop.
Around the holidays, the Library is decorated nicely. There is a huge Christmas tree, a live nativity scene with real animals (e.g., camel), performers, and carriage rides ($7 for adults). If you do plan a visit during the holidays, come early (before 5pm) or plan to wait in a line off of Billy Graham Parkway to get in (they stay open until 10pm during the holidays).
This place will definitely win points with family members or visitors who have any affinity to Billy Graham...and one that you could visit multiple times.