I've used DDG for some years now, and never had the problem switching and needing !g that others describe. (I use things like !w to search specific actual sites, but not to change global search engine.)
The only thing that bugs me is regional result relevance. It gives you a toggle on/off for present country by IP; as far as I can tell it has no effect.
I get /en-us/ and amazon.com as (all) the top results whether it's on or off.
As a 99% DDG user: I've always had better results with Google on specific tech problem-solving searches. Not sure how to explain it but it feels as if Google Search understands better the significance of the word order I'm using in order to give extra context. With DDG performing the search it's like I can tell from the first result that it really didn't get at what I was trying to figure out. How is Google so much better that that? It's been this way for years.
Still this isn't enough to take me away from the bangs and additional speed and privacy.
(Even when I see some joker/SEO is e.g. abusing Unicode to get bolding in DDG search results, saw that the other day)
Maybe it's because for me it's just locale (UK, en-gb) and not language? I don't know, it doesn't work well for me though.
If Amazon appears in the top 'web' results, it's always amazon.com (not .co.uk) however toggled. The sponsored links in 'shopping' results are always amazon.co.uk & £-figures though, however toggled.
Company websites, airlines, booking systems etc. that I know I'm going to need the /en-gb/ variant of invariably appear in results as /en-us/ URLs.
The only thing that bugs me is regional result relevance. It gives you a toggle on/off for present country by IP; as far as I can tell it has no effect.
I get /en-us/ and amazon.com as (all) the top results whether it's on or off.