Rumion is a great addition to the rather small group of affordable 6-seaters in the Indian market. Today Ertiga, XL6 and Carens (a bit expensive) are the only options for people looking for a true 6-7 seater car. Triber is there but its underpowered and last row can hardly seat adults.
Although it seems more expensive than Ertiga, I think the Toyota badge is worth it since many users don't want to buy the Suzuki brand. Overall I think it is a great people mover - with decent power, safety and features.