Every time I hear about these certification tests I can't help but think how useless they are. Mainly because they can't be trusted. They don't have any peer review (except when we experienced people take the tests and laugh at the mistakes :-)
Occasionally though, I have the idea that there could be a "good" certification test if renowned perl experts could review the questions/answers to ensure that they are kosher. Which would be worth more to perl people: I just scored a 98% on brainbench's perl test or I just scored a 98% on a test that was composed of questions reviewed by Larry Wall, Randal Schwartz, Mark Jason-Dominus, Damian Conway, and Abigail?
My idea has never gotten much beyond this "wouldn't it be neat if ..." stage but maybe someone else could run with it and see where it leads.