Better Performance - LEFT JOIN or NOT IN?

Which method of T-SQL is better for performance LEFT JOIN or NOT IN when writing query? Answer is : It depends! It all depends on what kind of data is and what kind query it is etc. In that case just for fun guess one option LEFT JOIN or NOT IN. If you need to refer the query which demonstrates the mentioned clauses, review following two queries.

USE AdventureWorks;
GO
SELECT ProductID
FROM Production.Product
WHERE ProductID
NOT IN (
SELECT ProductID
FROM Production.WorkOrder);
GO
SELECT p.ProductID
FROM Production.Product p
LEFT JOIN Production.WorkOrder w ON p.ProductID = w.ProductID
WHERE w.ProductID IS NULL;
GO


Reference : Pinal Dave (http://www.SQLAuthority.com)