sqloledb vs sqlncli - Performance difference or just feature set?
I talked to Erland Sommarskog about this and here is his response.

I attended a presentation as PASS 2005 about SQL Native Client. The
then-PM for SQL Server Client said that for ODBC they had achieved a
20% perf improvement, but for OLE DB, it was about even.

But since SQLNCLI provides more features, that is probably the provider
to use. Then again, with old ADO a lot of the features are unavailable
anyway.

HTH