Even with 2008R2 we seemed to get better performance natively than with LiteSpeed - LiteSpeed really saved us with SQL 2000 and 2005, but the day we got 2008R2 - boy that was fast!
Stats for a 120GB database, full backup:-
SQL 2000 native - 90 minutes
LiteSpeed - 30 minutes
2008R2 native - 10 minutes