We use C2 because we are required by the government to do so.

From what I undertand, C2 audits all events.

The events are written to 2000MB rollover files located in mssql\data.

One disadvantage is that if SQL Server cannot write to the audit file used in C2, then SQL Server will automatically shut down!

If I weren't required by the government to enable C2, I'm not sure I would use it.