I already Pass the Java SCJA exam using the Whizlabs products, it will help you a lot if make all the test and score very high in the Final test. Try to concentrate in the section of Algorithm Design an Implementation, because the exams questions are more hard that the ones in the simulator.
Don�t take much confidence if you score high in the simulator try to master the toughest topics.
I have tried the Whizlabs practice tests on just one occassion, SCMAD, and I was really dissapointed the practice exam was not of much use to me for that cert, in fact the SUN E-practice exam was much better.
MCPD (Enterprise Application Developer, Windows Developer, Web Developer - .NET 2.0), MCTS (Windows Apps, Web Apps and Disbributed Applications - .NET 2.0), MCITP (Database Developer & Business Intelligence Developer - SQL Server 2005), MCAD, MSCD.net, SCJP 5, SCWCD 1.4, SCBCD, SCMAD, SCDJWS, SCJA
My experience with Whizlabs' exams has been hit-or-miss really. I found that the UML product for IBM's 486 was fine, but I would agree that the SCMAD practice could have been better. You might take a gander at the demo you can download from their site (assuming it's like their other tests and offers a 'free taste'), and judge quality for yourself.
Theodore Jonathan Casser
SCJP/SCSNI/SCBCD/SCWCD/SCDJWS/SCMAD/SCEA/MCTS/MCPD... and so many more letters than you can shake a stick at!