Well, I went to this movie tonight. I won't give anything away, but damn if it isn't a terrifically fun film! Unfortunately, the "handheld" camera-work from the second movie was retained, and most of the fight scenes are way too shaky. I'll never figure out why filmmakers started using this method a few years ago, much less why they persist in using it.
But it's a good movie anyway - lots of action, very much in the same vein as the first couple. There were definitely a few things that made me chuckle, not because they were joke-funny, but they were discordant-funny. Moments that just don't fit. Regardless, if you enjoyed the first two, you will definitely enjoy this one just as much.
Finally, you can absolutely forget about this one having even the slightest thing in common with the book (much like the second film in that regard).