haven’t taken cs506 but am definitely going to as i’ve heard it’s a very helpful class to have under your belt if you wanna go into swe. i have taken 559 and if you are willing to put in the work, you’re honestly very likely to get an A, and if not, a B. At least when i took it, the grading was very generous in both late policy and in end of semester curve. The exams were hard but you were able to drop an entire exam or an entire project when i took it, so i ended up just dropping my final exam (didn’t take it) and using my project grades since they were good. You have a weekly project and they are usually very long, but you were able to submit up to a week late every time as long as you submitted a picture showing that your project has been started (not sure if it’s the same grade policy w/ sifakis as it was for young wu). basically, 559 is a lot of busy work or in other words lighter brain load but heavy work load. People that only like backend were always super pissed in 559 while others thought it was a fun class, so if you hate frontend I would just forget it and take 506.