Though, both ACEIs & ARBs act on RAAS, more complete RAAS blockade with ARBs than ACEIs is reasonable to produce different clinical outcome.
Further, since ARB actions are more specific to RAAS, hence have a better safety profile wrt dry cough, angioedema. On the other hand, ACEIs act on kinin system as well (bradykinin, tachykinin) leading to side effects.
Article Angiotensin receptor blockers - Advantages of the new sartans
Better metabolic profile. Telmisartan activate the PPAR gamma pathway that improves the lipidic, glucose and metabolic of profile. BTW every therapeutic decision should made in a patient-based fashion. There is no stablished recipe for hypertension.