That depends on what you are trying to do and what you are trying to achieve.
Your DNS:
Complete control over your DNS, you can make your changes, have multiple failover setups and won't cost you additional to set up a private DNS
Using Premium DNS:
Depends on which one you are choosing but can take of things like DDoS protection, Anycast DNS, CDN, etc. all integrated, so you go through less hassle.
It depends on what you are trying to achieve and based on that you can make a decision.
Your DNS:
Complete control over your DNS, you can make your changes, have multiple failover setups and won't cost you additional to set up a private DNS
Using Premium DNS:
Depends on which one you are choosing but can take of things like DDoS protection, Anycast DNS, CDN, etc. all integrated, so you go through less hassle.
It depends on what you are trying to achieve and based on that you can make a decision.