They all provide different content and it's all presented differently. As a very rough introduction, the following applies: Sophia.org - Offers only lower level (LL) courses. They are an affordable way to get your gen ed requirements out of the way. Also, inexpensive electives. Because of their low cost, you want to fill up your degree plan with as much of Sophia.org as you can. Study.com - Offers a mix of LL and UL (upper level) courses. Due to the way they grade their courses, they are arguably the easiest way to get the necessary UL credit. Much of their UL catalog is unique. StraighterLine - Somewhere between SDC (study.com) and Sophia as far as both ease-of-use and cost are concerned. They only have LL options, a few of which are unique if you need/want them. Their exams use ProctorU, which is a love-it-or-hate-it live proctoring system. Coopersmith - Both UL and LL courses. They give you information on a textbook which you're supposed to purchase yourself (generally not necessary) and PDFs or PowerPoint presentations to study. When you feel like you know the material, you schedule an exam with ProctorU. They have several courses that you can't find anywhere else, including "Special Events and Meeting Planning" and "Training and Development". Davar - Both UL and LL courses. Nearly identical to Coopersmith in concept except a.) cheaper (especially for business classes) and b.) they let you choose whether you want to use RPNow or ProctorU as a proctor. If you like their format, their business classes are cheaper than Study.com if you use RPNow as a proctor. They don't really have any unique offerings but they are also cheaper than Coopersmith. Saylor Academy - Both UL and LL courses. You might come across this one as you do research. They offer free study materials and are only $25 per exam and they do offer several business exams. However, they use ProctorU and they are extremely slow to respond or to grant credit. They are generally to be avoided unless you have no other options.