File or Block target for SQL 2008 DB and Log partitions

Is there a recommended type of target to create for SQL 2008 server data and log partitions? I have looked through the forums and was unable to find any previous threads relating to the subject.

I have done some testing with both types with the SQLIO tool and the differences in IOs and MBs did not seem significant. Are there some other variables to take into consideration due to the basic differences between the way block and file IO work?

Thank you for your help.

Paul