This is an excellent production of Agatha Christie's most famous novel. The setting and cinematography are fantastic. The isolated mansion is both extravagant and spartan, and the island gives you a wonderful "isolated from the real world" vibe. The characters are delightfully unlikable.
Yes, there are some changes made - some adjustments for modern sensibilities - but I love that the ending is closer to the book than most adaptations.
If you've seen any of the countless remakes (thrillers, horror, even parodies), give yourselves a treat and watch this treatment of the original.
I'll preface this by saying that I've never read the novel, but boy did I love this miniseries. I was constantly trying to figure out who was doing the killings and I did not get there until right before the reveal. It is an intense and well acted - even the island setting adds to the excellence - mini series that keeps the viewers on their toes.
I've read that this is the first British adaptation in many years that has used the original ending of the book and not the play. I'm personally a fan of this ending and think it makes a much bigger impact on the viewer.