This week's book giveaway is in the OCMJEA forum. We're giving away four copies of OCM Java EE 6 Enterprise Architect Exam Guide and have Paul Allen & Joseph Bambara on-line! See this thread for details.
HQL, Criteria and NamedQueries are trandformed into PreparedStatements, so there cannot be any difference (for the same statement). Native SQL might be faster, because you can do some handmade "magic" Hibernate cannot do.