Outstanding - I enjoyed this more than all of the fantasy series I have tried apart from Game of Thrones, and it is not far off that at all.
It feels grown up, epitomized by a constant thread of realistic brutality and a complex story. Yet it is lightened by a growing fantastical element and great humor.
I feel that it is less beset by tropes than The Stormlight Archive for example, though it is not free of them! Still expect mysterious wizards, and rough brutes from the cold North.
Despite its decent length the whole (very entertaining) book is groundwork for the rest of the series, it promises much, I bought the next one immediately!