i will say some thing about 2 cars....
both are from Toyota,,i think both have many good features,,but its upon you what you like,,,actually vitz has some good curves and good shape which makes it a popular choice of the market, its also little expensive then passo,,engine are almost the same...but one thing which can be an edge for Passo is the price ,,but if you see resale value ,,Vitz is car of the market and Passo is still struggling in Pakistani market.