The GL and CEM 11+ exams are different in terms of their format, content, and style. However, it's difficult to say which is harder as it depends on the individual's strengths and weaknesses. Some students may find the GL exam harder because it focuses more on multiple-choice questions and time limits, while others may find the CEM exam harder because it is more focused on problem-solving and reasoning skills. It is important to note that both exams are designed to challenge students and assess their abilities, and it is up to each student to prepare and do their best on the exam they are taking.