Ottke was an excellent boxer. Nothing special to look at physically and quite a dull style. But very good defence and high work rate with light but technically correct scoring punches. Also because of his correct technique he did score a couple of one-punch KOs even though he had a low KO percentage.
Some of the decisions may have gone the other way had he been fighting in the US but decisions are debatable. He was never beaten nor seriously hurt throughout his career and also went to three Olympics as an amateur without winning a medal.