Difficult choice! I’ve owned both (albeit the previous gen RAV4) and enjoyed them immensely. They both will rust, so have a good feel along the sills. If you can, take both for a test drive and sit in the back afterwards to consider the amount of space for passengers, and look at the boot size. I always had the back seats down as it was just me and my dog, so can’t advise on space.
Subaru parts are expensive, and not always easy to come by. Check the MOT history on both. Maybe offer the private seller £300 less and be prepared to walk away. It’s quite a high mileage.