Top positive review
Very good quick reads, perhaps for the beach or a flight. Not for kids.
Reviewed in the United States on May 21, 2016
This review encompasses most of the series - I've read almost all of the books except a few short stories/other stories that aren't part of the individually-published books (and the series finale is due soon so obviously I haven't read that).
Hearne can write, and the stories are entertaining enough for a quick read. The books are heavily derivative of Jim Butcher's Dresden series, and there's a lot of very obvious borrowing going on (examples: the charms O'Sullivan draws on vs Harry's charged jewlery; Harry's skull Bob vs Oberon the hound), but Butcher is able to flesh out his characters a bit more over the series, while Hearne's characters remain pretty much inscrutable. Hearne doesn't give us enough character development to allow us to get a real feel for the characters' motivations. For example, the main character is a Druid and a protector of Gaia, but at the same time he could be characterized as a sociopath who would kill a person in a heartbeat and not think twice about it. Yet we don't find out why he's like that, except that the guy's been around for over 2 thousand years and so perhaps he just doesn't care about regular mortals any more.
Despite the lack of deep character development, I found these books humorous, enjoyable, and the plot moves briskly.
I also found these books to be somewhat educational - for example, several parts of the series talk about the gods of different cultures (you can see Gaiman's influence in here as well, as the gods are still around because people still worship them or remember them). However, not all bits are accurate so be sure to check them out before quoting them. One admittedly minor sentence that was wrong but that stuck out for me was a causal line about Orvis, a chain of fishing/outdoorsy stores: Mr. Hearne, you may have seen these stores in England, but Orvis isn't British, it's American: According to Wikipedia, "Charles F. Orvis opened a tackle shop in Manchester, Vermont, in 1856." Again, I'm nitpicking here and this only stuck out for me because I'm a fly-fisherman.
This series is not suitable for young children, as there are many sexual references and a lot of graphic violence.