The main differences are the volume and handling: Trump had hundreds of classified files (thousands of documents total) stored haphazardly at Mar-a-Lago, leading to federal charges including obstruction, while Biden had a much smaller number (around 88 documents/notebooks) from his VP years, which his team voluntarily disclosed and cooperated with investigators to retrieve, resulting in no charges for him. Trump fought retrieval and allegedly tried to hide evidence; Biden's team immediately notified authorities and returned materials.