At first, "test-optional" certainly sounds great. It would be much easier to apply to colleges without all of the stress and effort of taking the SAT & ACT. When you look at the bigger picture, however, skipping these important tests isn't a great option at all. Without SAT or ACT scores, college admission committees place significantly more weight on your GPA and extracurricular activities. If another student with comparable grades and interests submits excellent test scores, the committee will be much more likely to choose that student over you since he presented a fuller picture of his achievements. Additionally, most scholarships and financial aid opportunities require SAT / ACT scores.

The short answer is: you should take BOTH! Colleges accept either test score, and they don't have a preference between the SAT and the ACT. Each test has advantages and disadvantages. The SAT contains fewer overall questions and gives you more time to complete each question, but the problems tend to be more ambiguous and purposely misleading. The ACT, on the other hand, requires significantly greater time management, but the questions are much more straightforward. Oftentimes, a student is better suited to one of the tests. His ACT score, for instance, might be considerably higher than the equivalent score on the SAT. The best way to get your highest score is to take both tests a couple of times.