Apress' Pro Git is a better book than O'Reilly's Version Control with Git. The O'Reilly book tries hard to educate you about the repository, but goes off into the weeds with details about history and branch management that overwhelm a user who "just wants to use the damn thing." The Apress book has a section on what goes on within the repository, complete with illustrations of blobs, pointers, trees, and so forth, but by eliding the blobs when talking about branches, and only going into detail when necessary, it makes the branch and merge process much easier to understand than the O'Reilly book.
Also, since I'm using Git on top of SVN, the Apress book's section on using Git with other repository software is sufficiently technical without, again, overwhelming you with the details.
Kathy Sierra once posted about Just In Time vs Just In Case Learning. The O'Reilly book quickly becomes a "just in case" book, whereas Apress' book is much more "just in time." The Apress book supports my mantra, courtesy of Bre Pettis: "Pretending you know what you're doing is almost the same as knowing what you are doing, so just accept that you know what you're doing even if you don't and do it."