I actually tried their crypto ads, out of curiosity. I had some BATs collected, then I reinstalled my machine, used their backup code to import the wallet again, but it showed zero value. I contacted them about this, never got an answer.
The sync was causing a crash for some people, so they turned it off for everybody. It was off for at least a week, and maybe even now. But even when it was turned on, it didn't sync properly between my iPhone and my laptop.
The browser frame is rendered weirdly both under xfce and kde. I had to resize the window and maximize again, to get the min/max/close buttons properly rendered, and make some random border disappear.
There were sites where I couldn't log in even after turning off the shield.
On my iPhone for some reason when I searched something in DDG, clicked on it, then went back, DDG was rendered, then tried to scroll, and the previous site started bleeding through from the bottom of the screen. The URL bar showed DDG, but nothing was clickable. Refreshing the page didn't work, so I had to force close the browser and open again to see my search query. Interestingly Google seemed to be working, although I only use it for like 1-2% of my search queries, so I cannot be sure.
In the dev tools the audits tab didn't work at all. Couldn't connect an Android device for remote debugging.
In the end all the little annoyances just made me uninstall it, because for me it is just too much to put up with all these. It definitely has some interesting ideas, but I cannot recommend it just yet.