What's the best value Roomba with a self-emptying base?

The [Roomba j](https://www.amazon.com/s?k=Roomba+j&tag=wehavethat-20)7+ at $599 hits the middle ground without the flagship tax. You don’t empty it for weeks—the base auto-sucks debris into a sealed bag. It has self-emptying, smart mapping, and pet stain detection, unlike the older i7+ or pricier j9+.