I've read innumerable reviews talking about the superiority of the mini-series. I certainly can't agree on such a blanket statement. If you analyze all of the aspects of a video/film production, there are numerable areas where the film is arguably vastly superior.
Certainly, many of the comments are valid with regard to particular areas of the mini-series. Specifically regarding more threads (customs officers) and more developed threads (such as the Pakistani farmer and family). That said, I found Catherine Zeta-Jones' character much more compelling as the desperate women, from poverty to riches who "won't go back." That's a much more likable character than this cold women who didn't seem to have as much reason for her quick turn to evil. (And yes, I understand...her children. She was desperate; I just didn't see her as being as desperate.)
Further, while I appreciated some of the more fleshed out story threads in the mini-series, Benicio del Toro's character was very compelling. An anchor for the film. That thread was changed (as an alternative to the Pakistani family) in nothing but good ways. A fantastic adaptation. (Of course, I'm skeptical that someone so pure can exist within such a system, but I don't know enough about the politics of the nation to argue).
After watching the first episode of the mini-series, I actually rewatched the film. Why? I kept reading about the fantastic acting. I found the performances in the first episode of the mini-series to be borderline laughable. Certainly, this improved as the mini-series progressed. Now having just finished both versions in a few days, I can't agree that the performances in the mini-series reached the same level as, say, Benicio del Toro, who was brilliant in the film, though Ormand, Paterson, Shah, and Lindsay Duncan were very good. I also feel the police in the film far outclassed the mini-series. I was not impressed with the Germans throughout.
Finally, the dialogue, as delivered in the film, is much more nuanced. Especially in the scenes which are almost verbatim. "Careful, you're beginning to sound like your husband." as opposed to "HAHAHAHA! You sound like Karl." Again, I found some of the acting in the mini- series very unconvincing. This was a prime example.
Other superior aspects of the film, in my opinion: score, cinematography, editing.
Should I complain that the film wasn't longer? No. I think it was a fantastic adaptation given the format. The changes made stood on their own. I mean, would you sit in a theater for 5/ 7/10 hours. Of course not.
Mini-series: 8 out of 10
Film: 9 out of 10