It's great that Cards on the Table finally introduced the character of Ariadne Oliver, she was brilliantly portrayed by Zoe Wannamaker, she certainly added a zest and spark to the eccentric character.
The first half scores a ten, it is brilliant, it's lavish, deep, dark and utterly engaging, the second half I'd score a 5, it really does go off the boil. Personally I don't think the multitude of changes from the book benefit the screenplay, there are too many gaps. The biggest problem is with the last half an hour, it feels rushed somehow, and is quite at odds with the beginning.
It is however extremely well acted, Lesley Manville is magnificent as always, Alexander Siddig is excellent in his characterisation of Shaitana, a really different role for him. I really enjoyed Tristan Gemmill and Lyndsey Marshal I'm their respective roles.
Gorgeous costumes and set designs, they make it look decadent, but there are some horrible green screen scenes, which look cheap and amateur.
Suchet is so good as always, that bumps it up to a 7/10, it's not the best, but it has enough good elements to make it watchable.