aqua:-
same 3rd generation hybrid drive train. smaller 1500cc engine ( for more economy ) . cheaper plastics and weight reduction here and there.
rear seats are useless if u have kids above 6' . rear cramped as well
drives very well, economical . easy to maintain, sniffs fuel .
prius :-
same 3rd generation drive train. 1800cc engine , power ful
hi quality plastics , more spacious, more legroom headroom in rear, spacious boot .
large families can go for prius
small can opt aqua
rest is same