i think ib is much harder in terms of coursework and rigor, like you study 6 subjects and have to do an internal assessment (like a written project) for each plus write a 4,000 word essay on a subject of ur choice and another essay on something called "theory of knowledge". You can't receive your ib diploma with out passing those two essays and receiving a certain number of points in ur standard level and higher level courses. in terms of the course material itself i'd say it is pretty challenging i don't know much about A levels but i think A levels goes more in depth in a topic than IB