I don't have a comprehensive test suite for seeing how search engines perform but I use some random programming terms to see how well it avoids SEO/AdWords boosted content.

Searched for radix sort -

Mojeek:

1. Wikipedia (as it should be)

2,3. Stackexchange implementation specific questions

rest: quality blogs, pure text tutorials

Google:

1. GeeksForGeeks

2. Wikipedia (seriously?)

3-10. all "blogs" that churn out the same content as geeksforgeeks (progamiz, javatpoint, tutorialspoint, etc)

DDG: Nearly an identical copy to Google's result

Personally, I'd prefer Mojeek to the Google/DDG results any day.

Will keep trying with complex queries, errors to have a better idea of how it performs, but still great work!

What's the competitive advantage compared to DDG? Why will this continue existing?

the duck is a wrapper for bing and this has its own index of results, if bing decides they don't want to service duck or they want to raise prices the ding dong, the duck is dead

Can't speak for them, but apparently they have been around for at least 15 years.

If you're looking for alternative search, I have to mention Kagi (https://kagi.com/). Not free, but totally worth it to filter out results like geeksforgeeks, tutorialspoint, w3schools etc.

Kagi uses the Mojeek API.