One question that has to be asked about short stories that are part of a series is what the purpose of them is. Are they strictly fodder for the fans? Or are they meant to serve as an introduction to the series to lure new fans in? Both of these series are set before Charming, and if I understand correctly the other shorts are as well, and some of them were published before the novel. However, while they manage to pack most of the things I loved about Charming into twenty-five and thirty pages, respectively (folklore, snark, and action), they didn't do much in terms of explaining the world. Terms like geas are used in both with minimal explanation. "Charmed, I'm Sure" is slightly better at getting across the idea that John Charming is both a knight who protects people against supernatural creatures who threaten the illusion that they don't exist and that he is also a sort-of-werewolf. But if I read either story without having read Charming first, I'm not sure I'd understand how this universe works or who Charming is. Granted, I had to skip "Don't Go Chasing Waterfalls," so it is possible that all of the short stories are meant to be read in order, in which case I would have gotten a bit of exposition in "Charmed, I'm Sure" and a bit more in Waterfalls before understanding everything by the time I got to the third one. But whether the stories are meant to be read after the novel or read all together as a unit, they don't individually act as good introductions to the world. But they are wonderful for holding me over while I wait for the day when I know another novel is coming.
Therefore, I recommend that if you enjoy The Dresden Files or really any other magic detective style Urban Fantasy (even though that's not exactly what this is, it hits the same buttons), you read Charming ASAP, and then proceed to read the shorts.
My previous review of Charming can be found here: http://unreachableshelf.weebly.com/1/post/2013/10/charming-by-elliott-james.html
Overall Grade: A