Did you try all of them?
What made you stick with the one you are currently using?
I became fully aware of Control D only yesterday as the name was vaguely familiar to me when I heard it and for Adguard DNS well I thought it was a normal-ish DNS service like 1 1 1 1, quad9, Google, etc... (not that user configurable).
I tried looking for some reviews and discussions comparing the 3 but found almost nothing about Control D and Adguard DNS but I did stumble upon Control D CEO 2 blog posts comparing Adguard DNS and NextDNS to Control D.
There seems to be not that much talk about these 2 unlike NextDNS which seems way more popular, if I'm correct then what made it way more popular and known?
I bought Control D's black friday deal last year and can't really complain about their service. Also includes some nice blocklists. But their interface is a bit confusing and slow to use.