These are quite different vehicles in terms of their physical size. While older generations of the RAV4 were known as compact SUVs, the current model is resolutely mid-sized. None of which is to say that the Yaris is cramped but it is a size-division smaller, so if you often carry people in the back seat or your family is growing, the RAV4 might be a bit more future-proof. However, in driveline terms, the Yaris is the one that is truly future-proof thanks to its hybrid driveline. If most of your driving is around the city and suburbs, you might be surprised at just how efficient a modern hybrid can be. On the highway, there's less to be gained form the hybrid layout, so take that into account, too. The other thing to consider is what happens a few years down the track at trade-in time. The RAV4 is question is already one generation older than the Yaris, and the hybrid Yaris is almost certain to be worth more as a second-hand proposition five years from now. Which means the latter will probably be the cheapest to own over that time in a wholistic sense.