The first search engines that I used were Ask Jeeves, Excite, and Altavista. You probably couldn't even recognize those names now. Then, I got my first email address, @yahoo.com, and learned that Yahoo! was a search engine too. So, I switched all my searching over to there as it just made life simpler.
Google finally came along and changed search as I knew it, forever, by providing more accurate search results.
I'm now hooked on Google, but I know that they hide and derank pages that could be exactly what I'm looking for, having me go pages deep to find what I searched for. Because of that, I'll now switch between Google and DuckDuckGo (Duck) to get the best results I'm searching for.
I've maybe touched Bing once, and it turned me off that it was essentially a clone of Google's homepage at the time. I'm sure if the UI was different, I would've used it more often to see if it gave good results.