The Princeton Review, a test-preparation company, believes that the ACT is a fundamentally better test than the SAT. The Princeton Review, indicates in its book, Cracking the ACT, that it favors the ACT because it finds the ACT exam questions less ambiguous and more knowledge-based.
The ACT (unlike the SAT) does not take points off for wrong answers, making it to the advantage of the test taker to answer or guess at every single question. Instead of having the writing test first like in the SAT, the ACT offers the optional writing test after all parts of the basic test have been completed. With few exceptions, the ACT does not test for vocabulary.
The math component of the ACT includes trigonometry, a topic that is not included in the SAT Reasoning Test (although it is present in the SAT Subject Test covering math). One important policy difference is that the ACT does not allow any calculators with algebra systems, including the popular TI-89.
An important difference is how the scores are sent. When sending SAT scores, every score received is sent. The ACT allows the person to pick which scores from a certain sitting to send. This is referred to as "score choice", which had previously been offered by the SAT.