I teach CIE AS math classes to a friend (I'm with Edexcel) and I assure you there is a minimum difference. In fact, I found CIE M1 and M2 easier than Edexcel M1 and M2, but this is not true for pure drives. Looking at the AQA documents, they seem easier. If Edexcel documents are difficult but you only need 50% to approve them, AQA documents are easier, but you need 70% to approve them (fully composed numbers), then you need to keep that in mind.
Both exams are considered to be of the same level of difficulty in general, with differences of opinion as to the difficulty of the subject. One example is that, CIE has a reputation for being easier than Edexcel for English and more difficult for mathematics. Both Edexcel and AQA have their non-calculating role as paper 1, while OCR differs by placing non-calculator paper in the middle of the series. Below is a table showing the key differences between the content of Edexcel GCSE Computer Science and OCR GCSE Computer Science.
Edexcel is more focused on the UK, so its difficulty level and structure of courses and roles is more compatible with the UK system. Edexcel is much more difficult than cie and requires a lot of thought, but the qualification limits are much lower than cie, since you can get a higher score in both works in Cambridge. If you are looking for an online review, Third Space Learning offers a library of free online gcse math review lessons that can be used for all GCSE mathematics topics, from algebra to statistics, as well as a large collection of GCSE mathematics worksheets, questions from GCSE mathematics and past mathematics from gcse papers. While these questions are predominantly for the OCR and Edexcel exam boards, due to the fact that all exam boards must now broadly examine the same content, they are useful when preparing for the A Level math exams on the four exam boards: OCR, OCR MEI, Edexcel and AQA.
It would be wise to look carefully at previous papers to compare the styles of gcse math questions and paper presentation to make an informed decision about what would be best suited for your students. Mastering Mathematics and Problem Solving books are good sources for applied and interspersed questions, especially useful for increasing student exposure to questions in a variety of contexts. The fact that Edexcel had bet himself in the middle was not a big surprise, while some students preferred simple OCR questions or more complicated AQA examples, most students preferred a combination of both. The three review boards had chosen significantly different approaches to structuring the questions; AQA had chosen to use less worded questions, but their questions were much more abstract, the OCR was much clearer, but the questions were much simpler, and Edexcel had established its position somewhere in the middle .