I'm currently in the Straighterline College Algebra. Honestly, it's been years since I took any math, so I knew I had forgotten a lot of it, but more than I realized. I thought I'd breeze through it pretty quick BUT after the getting a low grade on the second exam (only 15 questions worth 5 pts each on the first 4 exams for 75 pts each), I had to slow down and spend much more time on learning the material. I should finish before 8 wks and probably could have been a little faster, but I had another course I was doing this summer as well (that I just finished). So, now I'm concentrating on it. Since there are only exams with no homework or quiz grades, you have to get good grades on every test (well, or only do poorly on one as in my case).
My first test (over 1 chapter) I did well. The 2nd test (over 3 chapters) I bombed, the 3rd test (over 4 chapters) I did well again. Now I'm studying for the 4th test (over 5 chapters). You get 2 hrs on the first each of the tests which does give you adequate time to go back through the exam twice and double check answers. That was my failure on exam 2 - I didn't go back through the test and double check myself. The Final gives you the same 2 hrs, but I believe has many more problems on it (like 40 questions still 5 pts each for a 200 pt final). I'm hoping completing 40 questions in 2 hrs is doable for me - I'm a bit worried about that. You also have to call in and get a password to take it. There are options to proctor as well, but my college didn't require it. You need to check with wherever you are transferring the credit IF they will accept it and how they'd like to received it (direct through Straighterline or ACE). My college said they would accept it directly, but cautioned me not to take any additional because they would only take the one course.
If you take the course and don't get a 70%, you will have to retake it, but they will only average the grade (not replace). I found a coupon code online so my course was free (worth $39), so I just paid the $99/month (actually only 28 days). I'm in my second month (another $99) which I had hoped not to have to pay, but I decided better to slow down and improve my scores then be forced to retake for an averaged grade.
In order to understand some concepts, I did have to look elsewhere online, but there are videos and an online presentation of concepts plus links within the course to more information. As for the book, I didn't buy it. I think there are enough youtube videos and online math information that it wouldn't be required, but I cannot tell you if that would have helped for me to work the recommended problems assigned in each chapter.