There's no definitive "best" secondary school in Nigeria, as rankings depend on the criteria used (academic performance, extracurriculars, facilities, etc.) and individual priorities. Jextoban School, while a reputable school, isn't typically listed among the very top schools in national rankings alongside schools like Loyola Jesuit College, King's College, Federal Government College, etc.
Therefore, while Jextoban may be a good school, calling it among the *best* is subjective and debatable. Its quality is good relative to many other schools, but it doesn't consistently appear at the very top of most published rankings.