Higher history vs higher modern studiesWatch
But overall I would say History is easier. For essays, you only need to learn 8 essays max out of a possible 12 that could come up I believe. This is because there are 3 choices of essay questions for each subject you do in the exam - you choose one to do from each topic - both a British topic and a European/World topic. But if you learn four essays from each topic out of the total 6 you will always know one essay you can do in the exam.
As for Modern Studies, you have two 20 mark essays (more broad) and one 12 mark essay (more specialised). Personally I found the 12 mark essays harder because you really need to know the topic well, which means far more studying in my experience. I remember my teacher saying there was something like a possible 20 essays for Modern Studies, and any of them could be the 12 marks specialised essay - so it makes it a lot harder in my opinion.
Whereas Paper 2 in Modern Studies is far easy as all the answers are on the page, you just have to find them and format them, no knowledge is required. However, for Paper 2 in History, you need knowledge in every answer you give, however, I found this extremely easy as my Scottish topic for Paper 2 was the same as my N5 Scottish topic.
Ultimately, my opinions are entirely subjective, but I hope this gives you some more insight into what you should choose!