First, this is the kind of series the Brits have shown a knack for, riffing off normal life situations into something creepy and unexpected. (See for example UTOPIA, the original UK version, also reviewed by this scribe.) So even though this is a clone of a European show, it is a natural for English audiences.
Second, the casting of Bill Hurt suggests to the cynically-minded that series was done with a pre-sale to the US market already in the works, with Hurt's job to make the transition more comfortable and discourage yet another "forced cloning" of the show in the US market, a move that more often than not wastes money and creates an inferior product.
Third, the casting is to die for. Gemma Chan is perfectly cast as the main "bot" and reminds this cranky old reviewer of what happened when Barbara Eden first appeared as a family "genie" in the US decades ago. It is now agreed by TV historians that subliminally this appealed to many male viewers who stayed loyal to the show for reasons well beyond the story arc.
And Colin Morgan, once the Merlin of legend, is an under-rated actor who can only make the show better over time.
Looks like a winner to me.