I agree that the DDG results, especially for software development related searches, are often worse than searching Google or StackOverflow directly. So here's my workflow:

1. Search DDG. If I find a decent result, I stop here.

2. Append !so to the end of the search. This searches StackOverflow directly. If this works, I stop here.

3. Append !g to the end of the search. This searches Google directly.

This way Google becomes a last resort.

Also worth noting that you can actually navigate DDG search results using vim keybindings without the need for a plugin: something Google dropped support for a few years ago.