• The one for SCJP 5.0 (CX-310-055) from Whizlabs
• The one for SCWCD 1.4 (CX-310-081) from Whizlabs
• The one for SCBCD 1.3 (CX-310-090) from Whizlabs
• The one for SCDJWS (CX-310-220) from Whizlabs
• The one for SCEA (CX-310-051) from Whizlabs
• More recently: The one for SCBCD 5.0 from Enthuware

License

Enthuware uses a pretty normal end user software license, while Whizlabs plagues the user with a complicated activation procedure, only to limit the use to three CPUs! So when the user upgrades the CPU or gets a new computer, the license is lost. The three CPUs for which it works have to be chosen within 6 months after the purchase. That makes it pretty much useless for what I bought it, which is to keep my knowledge about topics that I currently don’t need at work up to date. Whizlabs simulators cannot be used for that. This is not much of an issue when the user wants to learn for a certificate and will never need the simulator again afterwards.

Learning process, repetition scheme

Whizlabs simulators have certain features which try to adept to the user (“adaptive testing”). As far as I know they do not follow proven methods from the field of education science, though.

Enthuware’s direct support for such features is limited. However, its comment system provides great flexibility for custom systems. My article Effective Enthuware describes how to use the Leitner System in the Enthuware Test Studio. That is the system for this type of learning.

Supported Platforms

Enthuware Test Studio requires JRE 5.0. The Whizlabs simulators support all common Microsoft Windows versions.

Errata

Enthuware Test Studio provides a direct link to the Enthuware forum post in which that question is being discussed. That can be helpful to find out if the proposed answer is incorrect, but recently I was usually the first one to check that out, so there were no other comments about that question.

Useability

Whizlabs has a Flash based GUI. It works well, but most things must be done with the mouse.
Enthuware uses the common key and mouse bindings for GUIs (Swing with system’s default L&F).

Price

For most exams the Whizlabs products are a little more expensive than the Enthuware products. For example Whizlabs SCBCD 5.0 Preparation Kit for USD 74.95, Enthuware EJB+ Full Version for USD 29.00.

Question Quality

The big unknown. I do not know anything about a conclusive study regarding the question qualities. They are both at least okay.

Question Quantity

Untransparent for Whizlabs products, and varies from product to product.

Conclusion

I recommend the Enthuware products. The knock-out arguments are the license and the Leitner System support. A really nice objective test from a huge organisation would help, like the tests we have for cars and such, a test which would also examine question quality and study time / exam result ratio. But this market is just too small, so you have to do with subjective reports like mine.

See also the Effective Enthuware article.