As far as I can remember, they are both good. So if you can your hands on either or both go for it. Read and study both if you can (it will only enhance the learning).
Look on the CASA website and see if you can download the sylabus and any sample questions.
Get your highlighter and post-it notes ready and as you go through the questions start highlighting and posting (all legal as far as I remember as long as you don't write anything in the CAO's etc).
Good luck and let persistance be your friend!
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