Inquiry regarding used cars

Is a used XT6 a good choice?
It won't be for commuting,
but rather for driving with my family on weekends,
so I won't be driving much—maybe only about 10,000 to 15,000 km per year.
However, since it's an American car, the fuel efficiency is only 8.3 km/L. I'm also considering the Aviator in a similar class, and I'm debating which one would be better. The time to make a purchase is approaching soon...