Hey there, WGU student here having just passed C299. I got a score of 880.
I spent 2 months studying for this exam after having finished CCENT and CCNA in the February and March.
Resources used: Lynda's Lisa Bock CCNA-Her series is incomplete as of when I last checked in May. Good overall beginning resource. Pluralsight's Brandon Carroll Explained concepts well with great use of visuals. CBTNuggets Keith Barker- I'm normally a fan on Keith, but I think this series wasn't that good. The videos often dragged on for way too long and concepts were all over the place. Still recommend watching this series, but tapering expections.
For books: UCertify OCG- Light on information and doesn't cover everything. Would use to get a grasp of CCNA security. 31 days to CCNA- Best resource to use. Fills in the gaps OCG misses.
For practice tests: Kaplan practice tests on Plursight-Good intro questions. Boson- ABSOLUTELY NECESSARY. GET IT. Reading the answers to the questions taught me so much.
Miscellaneous: Read the Parka.
Thoughts: A lot of weirdly worded questions(go figure) and esoteric concepts and the most challenging CCNA compared to CCNA RS and CCENT.
Where I go from here: I'm done with CCNA for a while. Next WGU class will be a spreadsheet class.