One nice advantage of StartPage over DuckDuckGo is that you can search within the last year. For some reason DDG limits you to past day/week/month, but I find I use Past Year quite a bit, especially when looking for product reviews.
StartPage also lets you custom-configure how you want results, and it gives you a custom URL to use (instead of sticking a cookie in your browser): it lets you configure search mode, theme, number of results, and more. This is also useful if you don’t want to make Startpage your default search engine - you can just bookmark the link and use it when desired.
On one of my browsers I use DDG as the main search engine but I made my custom StartPage page my ‘home page’ so StartPage is just a click away in the Bookmarks Bar.