I am going to go with Matt here in that on a very busy system with off-hours slow time full recovery mode can allow optimal performance during the peak time by not having the tlog flushed automatically in Simple recovery mode. This assumes that you tlog is sized appropriately and you don't get autogrowths during peak time, btw. But everyone should already have that done on their systems anyway.
Best,
Kevin G. Boles
SQL Server Consultant
SQL MVP 2007-2012
TheSQLGuru on googles mail service