Thanks!
Given your particular situation, it sounds to me like you should not only buy QCSD, but buy 200 copies of it to give all your friends and family. :-)
More seriously, the overlap between QCSD and WPSCACC is actually relatively small---e.g., WPSCACC just has one short section about quantum mechanics, whereas that's at least half of QCSD. QCSD is also written in a much chattier style (but at the same time, it has more space to exposit basic material). I can't guarantee that you'll like QCSD, but I hope that gives you a sense for the diff.