MWI does not predict anything which could differentiate it from other interpretations of quantum mechanics. Otherwise it would be called theory rather than interpretation. The question of choosing particular interpretation is philosophical rather than scientific. If you dislike MWI you likely to choose another interpretation which would be similarly unprovable.
The main advantages of MWI are that it extends the area of applicability of the usual laws of quantum mechanics, and postulates that there are no distinguished observers.
The main disadvantage is that it postulates the existence of unobservable entities, far exceeding the observable domain.
It is also objectively deterministic but subjectively indeterministic, compared to totally deterministic Bohm mechanics interpretation and objectively indeterministic Copenhagen interpretation.