This thread seems to be still comparing the V-22 with a helicopter..which it is not.In Iraq the infidels had a shock when they realised that ,having pitched their camp outside the range of a CH-46 and expecting ample warning (noise and speed) of any attack,they found the V-22 could take off on missions in IFR conditions ,cover four times the distance at an altitude well out of range of ground fire ,sweep in a high speed relatively silently and be offloading Marines before they had woken up.
You don't need lots of guns and armour in that scenario!