[Zubersoft]

You really shouldn't see any performance issues with a larger library. There are no limits and some users have libraries with tens of thousands of songs. The only thing you will notice is that MobileSheets will take longer to start up as it caches information from the database. Also, if you perform any actions that impact the entire library (such as adding every song in the library to a single setlist), those actions will take longer. 

Mike