I've been using duckduckgo exclusively for a year now on all my devices and I'm loving it.
The whole point of a search engine is to give you what you're looking for, and ddg delivers. If I ever need to Google something, I'll use !g query. You can make it look really nice also by changing it from the Default theme to Basic.
I didn't realize you could do this on Android until I read this. I've been using DDG on desktop for a year or so. The trick is to visit DDG before you try to change your search engine. Otherwise, it's not listed as an option.
If you put "!g" at the start of your search, DDG automatically redirects you to the search result in google.
I've been using DDG as my search engine for about 2 1/2 years now, and I find absolutely no reason to go back to Google other than location search, and DDG proxies that easily.
Thus explaining why I'm mystified by what everyone is complaining about. For at least the last couple of years (whenever iOS allowed DDG as default search engine) I've used pretty much nothing but DDG. I'm guessing I've probably never seen an AMP page (certainly not that I've noticed).
For several months AMP regularly (70-80%) caused pages to fail to load from Google News through a Chrome browser on Android M. Often after several reload attempts it would work, but sometimes not. Loading through Firefox was always a work around, but URL copy and paste was annoying.
I figured it was just tehGoog reminding me to pay attention to other human beings rather than staring at my phone. Then they fixed it with some update, when they realized I was incorrigible (actually I never figured out why).
So that's what has been happening! I've been so confused lately as to why Google links would fail to forward me to the website I clicked on, leaving a blank page and a massive google.com query string in my address bar. Sometimes refreshing the page has not worked, forcing me to manually copy and paste the address off of the search results. Someone should write a browser plugin that uses the little green URL instead of the <a> in all Google links.
I got them very frequently (as a user). This coupled with the inability to turn off AMP finally pushed me to use DDG as the default search engine.