This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
If you are asking only about the difference in the title: Professional vs. Expert - I think they just decided to change the name but Expert looks higher than Professional.
Here is an interesting thread: Exam Story