I've passed the SA and Developer exams and found that especially for the Developer one, MOST of the questions were very similar to or exactly like the ones on Whizlabs. For the SA test I used ACloudGuru more, but also found the quizzes helpful.
I am now studying for SysOps and have found the Whizlabs quizzes SUPER difficult. I passed the Dev exam with 92% and literally have not passed one of the first 4 quizzes here. If they are representative of the actual exam, I have a ways to go in preparing.
