This question is not so easy to answer as it can depend on a number of factors. There is plenty of information to be found online about the differences between Odata en REST API's.
Mostly it will boil down to this:
If you want to share data between apps using Mendix Connect (fka DataHub) and work with external entities in your domain models then choose Odata.
If you are looking for a simpler and less standardised service then choose REST.