This week's giveaway is in the EJB and other Java EE Technologies forum. We're giving away four copies of EJB 3 in Action and have Debu Panda, Reza Rahman, Ryan Cuprak, and Michael Remijan on-line! See this thread for details.
What kind of benefits you are looking for? Performance benefits or concurrency? Optimistic/Pessimistic have their own advantages and disadvantages. I have used optimisticUpdates and found huge difference in performance as it holds locks for a very short period of time thus avoiding deadlocks/lock escalations/memory issues with database.