Not much to add beyond what others here have already said. After I discovered that the editorial assessment I was given included the instruction to revise content that is already live on the site (do they frequently publish things they're not happy with? will the work I did on my assessment be incorporated into page updates?), I have to admit my investment level took a bit of a nose dive. As a freelancer, taking four hours to do an in-depth assessment exam for a job with an unknown salary is already a heck of a gamble; feeling like there could be potential exploitation in the works did nothing to settle me. (To be fair, none of the work I did has made its way onto the site, and so this is probably paranoia on my part, but it shouldn't be a concern at all.)
Editorial assessment included a section on revising and clarifying live copy (eurgh), advising a writer on how best to go about testing for the 'best' of a given appliance, and deep revision of a full (unpublished) article. There didn't seem to be a style guide consistently applied (I asked about that in an email with my submission and was told my questions would be answered if the interview process were to move ahead), and the editorial voice can err on the side of casualness as opposed to clarity. The Plum profile was fun, but also somewhat time-consuming, and I'm not sure how it played into the process as a whole––it really seems like the sort of thing that would have led to a phone screen, which then would lead to the larger assessment, rather than having an applicant invest so much time at the outset.
There are definitely worse ways to spend an afternoon if you like word and logic puzzles or editing for fun, but unless your circumstances better adhere to their deadlines and you're able to get your questions about the position answered before you begin the assessment, I'd find a more productive use of time.
