The ACT and SAT have both rolled out some changes recently, changes which have made the tests much more similar than ever before. However, these changes do not mean that the ACT and SAT are interchangeable tests. There are still a number of important differences between the two tests. Depending on your personal testing style, you will likely score much better on one test over the other. That is why it is important for you to understand the advantages and disadvantages of each test so that you can get the highest score possible.