"By far the best way to prepare for the High-Level Certification exam is to take the official practice exams. [...] Purchasing the exams will provide you with two full practice exams that you can take at your convenience through your web browser."

(High Level Certifications 2005 - http://www.high-levelcert.com/perl.htm#WhatisonPerl)

(My italics)

So the exam (inevitably) costs, but beyond the fairly brief list of what concepts are covered on the exam, there is no way of making sure you know everything needed, other than to purchase the practise exams. And since TIMTOWTDI, there may be questions on a function that you rarely if ever use. We've discussed this before, but a lot of programming is down to style - if your style differs from the person setting the exam, chances are good you will fail.

We can't really say for certain whether the questions are well written without seeing them, and I for one am not paying to do so.

If High Level Certifications are interested in getting feedback from the community, I'm sure one or more of the senior monks would gladly cast an eye over a sample exam, provided they were free to comment openly.