I'm planning to prepare for OCPJP/SCJP 6. The main short-term reason is to get up to date with the new Java features and cover various gaps in my knowledge about Java that I have never really felt confident with. In the long run I'd like to get the SCJD and perhaps the architecture or other entrerprise-level cert. I have substantial Java enterprise programming experience but mostly with version 1.4 and only recently with 1.5. In my company they never really used many of the "modern" features of the language and you would never have to use things like concurrency, assertions, etc and just used a bit of generics here and there so I've forgotten most of it.
Now, I've heard good things about the K&B book "SCJP Sun Certified Programmer for Java 6 Study Guide" but recently also found out about prepkits like Enthuware, Whizlabs, etc (especially the first one)
so, which is the most effective way to prepare for the test, selft-study guide and mock exams or let yourself be guided by these software-based preparation kits?
Bando since you are an experienced developer, I don't think you'll face any issue with preparing from the K&B book. I think you'll be able to skim through some chapters which you already know very well. I've never used any preparation kits so I don't know what their contents are so can't comment on them...