O'Sullivan is highly regarded in the sport, with several of his peers regarding him as the greatest player ever and some labelling him a "genius". After losing 6–17 to O'Sullivan in the 2008 World Championship semi-finals, Hendry described him as "the best player in the world by a country mile" at that point in time. However, O'Sullivan sometimes lacks confidence or interest, and he has performed inconsistently throughout his career, with observers noting the "two Ronnies" aspect of his character.