gorhill has proven his integrity time and time again, and that's hard to beat. He works on uBO because he believes in it and not for profit. It's the one thing that I would value, especially in an ad blocker. This isn't to say that there's anything wrong with AdGuard though.
Yeah honestly unless the developer can demonstrate that they don't allow ads through from who pay them to be allowed, pretty much no adblocker is going to be fully trustworthy. There will always be an incentive, if the adblocker is popular enough, for the dev to take money from an advertiser to bypass the block.
If I did have to trust any adblocker though, it would be gorhill's.
uBlock is open source. Some people might object AdGuard Russian foundation, but they have distanced themselves from the conflict and employ people in Ukraine.
So I did some research into this and it’s complicated. Seems as though the founder is Russian, the business is registered in Cyprus and is under EU jurisdiction, and the team is all over the world with the majority based in Russia.
I’ve heard it’s best to avoid running both but unsure whether this version of uBlock is worth it.