According to the Daily News' Gatecrasher, the screen couple definitely haven't been getting along, and won't be the follow-up to Vince's romance with past co-star Jennifer Aniston. Just like her production company's moniker (Type A Films), Reese is coming to set ready to put in lots of work, while Vaughn wants to be laid-back. "Vince rolls onto set in the morning looking like he just came in from a night out, while Reese will arrive early, looking camera-ready. Then, Reese tries to force Vince into blocking out each scene and running through their lines as Vince tries to convince her that he's an ad-libber and wants to play around and see where the scene goes."
So far, however, this clash hasn't stopped production, but the source also says that Vaughn sometimes looks like "he just wants to kill her." Honestly, I can see both of their points. I'm sure it must be aggravating for Reese to have to fight to get cooperation in how she prepares, just as it's probably infuriating to Vaughn to deal with a Tracy Flick-type and not be able to just go along as he wants. Hopefully it won't lead him to the fate of Matthew Broderick in Election. We'll have to wait 12 months and see whether we can spot all that anger in their characters; if the rumors are true, we'll see just how good the two actors really are.