That is what I thought too when I first started using them. "They just aren't as good as Google!". I have found this to not be the case as often as I thought it would be. In fact, 90% of my searches I'd say never require me to leave Duck Duck Go to find the answer, that includes technical queries.

That isn't to say that DDG is perfect, but for the times that it isn't perfect tacking an !g or !b to the end of the search does the job.