Here are the steps for restore (although they can be terse)
1. Install Backup and Sync on new computer
2. Add an empty folder "Temp" to backup
3. Let the folder be backed up so that a Computers > My New Computer > TEMP is created on the cloud.
4. Go to cloud and move the top level folders in Computers > My Old Computer > Documents/Downloads/etc into Computers > My New Computer
5. Create empty folders with the same name on the new computer.
6. Add them each in the Preferences. In version 3.36+, the application will recognize that it exists in the cloud. It will then tell the user it will merge the folders.
It doesn't take anything away from the current Google Drive client. It adds more features such as adding more folders to sync, choosing whether the images in those folders get synced to Google Photos, adding USB media support, and deletion options.
It also has a lot of bug fixes over the older client.