Depends on what you want to carry
If just pods then a pod belt is most efficient
If you want to carry a lot of pods, without using the elasticated + loops then a vest can give you more space to fill with pods, but you still have to allow space to pull the pods
If you are carrying more things and spreading the load then use a vest, eg if you run a remote line and wear your cylinder, camel back, radio, even a fluffy or pull through stuffed in molle loops
When it comes to choosing a vest decide on a dedicated system with fixed pockets or a molle system that you can change to meet specific requirements