They're all "managed DNS" in the meaning of "someone else runs the infrastructure for you".
What you need to look at are your requirements, such as:
- Price per request volume
- Network size/Resliliancy
- Features such as Geo-based DNS and Anycast
Most registrars just allow you basic A, CNAME and MX records and not much else, just via a web interface.
If that's enough, as it is for most small sites (like blogs etc) then great! Otherwise if you need an API, or want to give different A records to different regions, then you need to shop around.