I generally prefer to watch "foreign" films in the original language with English subtitles, because I cannot stand the pseudo, toneless, unsympathetic, dubbed American voices. However, I don't consider this a "foreign" film as such, as it is essentially a British production, and have no problem with the characters speaking mainly English - although some German is used as well.
I think those viewers who have criticized certain historical elements in the characters, their roles, language, personalities and backgrounds, forget that this is, after all, a FICTIONAL account, albeit based on actual events. As so, writers have licence to change incidents, characters, speech, behaviour and so much more, to ensure that the script works in a film genre, and that we have not only an instructional and educational series, but also an ENTERTAINING one which you will want to follow, week after week.
This certainly hits the spot. Miep is engaging, funny, cute, courageous and very, very human. As is Jan - an ordinary "bloke", trying to do a very boring job to the best of his ability, until he is presented with a life-changing challenge. The Frank family and their guests, are all wonderfully presented as ordinary people, thrown into a horrific, terrifying situation.
But to my mind, the most impressive role is Liev Schreiber as Otto Frank. I remember him "fondly" as Ray Donovan and in other macho roles, but here he is underplayed, quiet, with a gentle sense of humour, but a core of steel, just trying to do the best for his family under horrible circumstances.
This series is to be commended for bringing the unknown story of Miep and Jan Gies to the attention of the entire world, thus it's selection of English as the main medium. It is compulsive viewing and I can hardly wait for the final two episodes - even though I know how this tragic story actually ends.