Part 3 of the Big Data Specialization was definitely mediocre. I no way do I question the technical expertise of the lecturers, but from the perspective of instructional design, the course was awful. The contents were presented in a dull fashion, the quizzes had a focus on replicating facts instead of showing comprehension and were not always constructively aligned to the videos, and I am not even sure what I learned from the assignments: I spent more time figuring out how to install the missing software components than actually using them.
Furthermore, you are forced to use a commercial software. While it can be obtained without further costs, you are forced to "pay" with your contact data, and you must opt-in to receiving emails. I really don't like that attitude. Additionally, when trying to install the software, my Ubuntu system informed me about quality/security issues. I rather installed the software in a virtual machine.