My girlfriend and I are in our twenties and she dragged me to both of these "for the lolz." The first one I saw in the theater while I was sobering up. This time a friend torrented both and we watched them at their place, with drinks. I'm not sure if it was the beer, the fact that I spent most of the movie surfing the web, or that the cam-job came with a laugh track and cut off most of the werewolf-dude's head, making him pretty easy on the eyes, but this one seemed significantly better.
By "better" of course, I mean less terrible. Seriously, the plot, script, and directing all contribute to making these movies unwatchable. The movie really focuses around the creators' perceptions of what it means to be an angsty teen, and I found this to be well characterized by the various drinking games I found online. If you don't know anything about the Twilight series, you could do worse than to try to glean insight from reading rules such as "Drink when Edward tells Bella to stay away from him, then stalks her anyway" or "Drink when Bella bitches and whines about something for no reason." Take this into consideration when weighing how much you really like your girlfriend.