I'm a Systems Reliability and DevOps engineer for Netdata Inc. When not working, I enjoy studying linguistics and history, playing video games, and cooking all kinds of international cuisine.
However, there are two other sites I find myself checking regularly when doing web development (not including documentation sites for specific libraries):
Stack Overflow, because sometimes it's significantly easier to figure out what I code I need to write to do something there than via MDN, especially if there's no quick and easy solution.
Can I Use?, because I care about making sure my site will work with a minimum of run-time checks for specific features (also, they have links to documentation on almost all of the features they list, which may (does in some cases) include better resources than MDN, especially for some of the more esoteric stuff).
For just documentation? Yes, absolutely.
However, there are two other sites I find myself checking regularly when doing web development (not including documentation sites for specific libraries):
Good point the second one. I didn't know it so I will add to my set of useful tools.