I did not do an extensive comparison to DDG but I would say it is definitely worth it. Been paying for awhile now and it blows away Google. And they are constantly adding new features and improving old ones (and finding new ways to improve their back end costs as well which makes it more sustainable).

I use search engines a TON though (especially for work) so 10$ a month is absolutely worth it for me. I am currently trying to convince my boss to buy it for our whole IT team