I caught the first two episodes last night. It gets off to a rather slow start as I've heard from many reviewers, but the eye and ear candy (cinematography, set and costume design, and soundtrack in DD Plus) are enough to carry you through. It's gotten a pretty low score on metacritic (47), as for some reason critics are comparing it unfavorably to A Game of Thrones. Comparing a historic period drama to a fantasy epic is like comparing Mad Men to Bewitched because both involve a handsome tall man who has a pretty blond wife and works at getting ahead in an ad agency. The user score on Metacritic, however, is 8.0 based on 79 ratings, which should tell you something.
The production quality of Marco Polo is simply amazing, fully immersing you in the world of 13th century China and Mongolia. And as the show progresses, the characters and story are getting more interesting as the pace picks up. You get the feeling you're being set up for something BIG.