Where is the User Presets folder?

Plugins store your user presets in a standard location which is dependant on your OS :

Macos :

On macos, your user presets are stored in this folder : 

~/Library/Application Support/Beatsurfing/<plugin name>/User Presets

for instance, for the 7DeadlySnares plugin, the location is :

~/Library/Application Support/Beatsurfing/7DeadlySnares/User Presets

the "~" symbol is an alias to your root user folder.  

the complete path is : 

/Users/<your user name>/Library/Application Support/Beatsurfing/7DeadlySnares/User Presets

Windows :

On Windows, it's the same principe, but the path is different :

C:\Users\<your user name>\AppData\Roaming\Beatsurfing\<plugin name>\User Presets