Udacity's whole proposition has always rested less on the lectures and more on everything wrapped around them, and reviewing this nanodegree fairly means judging it on that basis rather than pretending it is competing purely on the quality of its explanations. The content itself is a sensible modern tour of deep learning, moving from the basics of neural networks into convolutional networks for images, recurrent networks for sequences, a proper look at generative adversarial networks, and finishing with the practical matter of deploying a model so that it does something in the world rather than sitting in a notebook. None of that arc is unusual, and that is rather the point, because the same ground is covered, often in more depth, by free university courses and by excellent open material. So the real question is what you are paying for, and the honest answer is the structure and the feedback.
The program is built around projects you actually build and submit, and those projects are reviewed by humans who tell you what is wrong and how to improve it, which is a genuinely different experience from watching a free lecture and never finding out whether you understood it. Combined with deadlines and mentor support, that adds up to the external pacing and accountability that is the single thing most self-paced learners lack, and for some people it is the difference between finishing and quietly abandoning yet another course. That is the case in its favour and it is real. The case against is mostly about money and self-knowledge.
This is expensive for what the raw content is, and the subscription model means the meter is running, so a slower learner pays more for exactly the same syllabus, which creates a faint pressure to rush the very material you are paying to understand. The treatment of the underlying mathematics is lighter than an ambitious university course, so if depth of theory is your goal you may find it skims where you wanted it to dig. And the uncomfortable truth that any honest review has to state is that the entire value proposition rests on you needing the scaffolding, because a disciplined, self-directed learner can assemble the same knowledge, and arguably more of it, from free courses, open lectures, and a good textbook, paying nothing but time and willpower. So my recommendation is squarely conditional.
If you know yourself well enough to admit that you only ever finish when there is a deadline, a deliverable, and a human looking at your work, and the cost is something you can comfortably carry, this can be money well spent precisely because it gets you to the finish line. If you are honest with yourself and the answer is that you are disciplined and short on cash, then the better move is to take the free path, keep the money, and spend the difference on a textbook you will actually read.