My experience
Crypto Zombies is made of multiple chapters with interactive lessons, each teaching you a new concept and asking you to try the code yourself in the sandbox next to it. The concept looks a bit like Free Code Camp. It was fun to go through, even though it could get frustrating at times, with the editor marking my answer as wrong when I forgot a semi-colon (which did happen quite a lot) so I ended up clicking the button to see the answer quite a lot, and just copy-pasting it. Going through that process of first writing the answer yourself, then looking at what went wrong and correcting it is still helpful though (even if you end up copy-pasting a lot at some point).
Crypto Zombies doesn't give a broad overview of which tech-stack you would need to work with dApps, which means it's a good starting point to learn Solidity, but you would probably need some additional learning resources afterward.
You will learn
Solidity
Chainlink
Truffle
Oracles
Positive
✅100% free 💖
✅Beginner-friendly
✅Well structured
✅Gives a good overview of the main concepts
✅Easy to understand
✅You need to code yourself, which is good for learning
Negative
❌The answer checker is still primitive (it will count your answer as wrong if there's one space too much, or a semi-colon missing, which ends up being confusing since you don't know if your answer is wrong, or if it's just wrongly marked as false).
❌It seems like some parts are outdated (they announced some additional lessons, which are still not there) the GitHub repository shows some signs of life, but I am not sure how much time is dedicated to this project.
❌The lessons stay inside sandboxes. It's hard to know if the content is outdated or not.
❌If you're looking to learn everything you need to know to be a web3 developer, with just one course, Crypto Zombies is probably not the right one.
Further resources
If you want to see more resources to learn about web3, this page gives a great overview of them.