While they're not bad per say, they;re never detailed enough of a reference. 99% of my webdev searches are now "mdn <topic>" as MDN is typically the most detailed resource on the topic (short of reading the exhaustingly verbose standards).
Of course now that I search "mdn <topic>" for everything I'm not training google's engine to match <topic> with the mdn resource, which helps cement w3schools as the top result for the topic
If you're using Firefox you can also go to MDN, right click the search box and click "Add a Keyword for this Search...". It's (almost) like a DDG Bang but local to your browser (and for me it's a lot faster too).
It gets even more crazy once you realize Firefox is just saving a bookmark with a form submission template and you can make forms that "send" GET requests to data URIs and if you combine that with the keyword search you can run tiny web apps from your bookmarks using "commands" in your omnibar!
I find the ddg search results load faster and are better indexed than the MDN built-in search, same goes for most sites that do their own indexing and are also indexed on big search engines.
In my experience the search on MDN sucks, and I usually get much better MDN results by searching for "mdn <searchterm>" on DDG than I get for "<searchterm>" on mdn.
While they're not bad per say, they;re never detailed enough of a reference. 99% of my webdev searches are now "mdn <topic>" as MDN is typically the most detailed resource on the topic (short of reading the exhaustingly verbose standards).
Of course now that I search "mdn <topic>" for everything I'm not training google's engine to match <topic> with the mdn resource, which helps cement w3schools as the top result for the topic