I have used it as a default for at least 2 years. I'd estimate drop back to Google for 20-25% of specific "subject matter" searches, mostly around technology. Probably a bit less than that for general searches. Most of the time I run the same search on Google the results are very similar for the top hits. But Google does seem to produce helpful results that are not exactly what I searched for more often. DDG also ske…
It's basically replaced my TI-89 for years, I hate doing calculations with units by hand and it's super error prone to not include them in the calculations.
For everything else, duckduckgo has consistently provided a suitable result to answer my question for 90%+ of stuff, no worse than Google. It's super rare for me to check if Google has better results for normal things. I see them as a different ordering rather than superior ordering, so I think of Google more as an alternative than a fallback. They clearly both interpret whether a site is a good match using different algorithms but I don't know I'd say one is strictly superior.