One is not better than the other, they are just different methods and way of thinking.
You can use both permissions system on the same path without problems.
They interfere with each other when modifying owner's, owning group and other permissions: when setting current value for these from setfacl, it will actually set the posix permission, not the ACL one.
Posix permissions only allows an owner, owning group and "everyone" permission while ACL allows multiple "owning" users and group.
ACL also allows setting default permissions for new files in a folder.
You can add more permission management on top of both with apparmor or selinux for stricter control.