The base of the litter box has a groove molded into the bottom so when sifting the litter it's a little difficult to get into that area. The box is very sturdy even though the lid doesn't latch down to the base. That isn't a problem for my large cats and they haven't knocked it off. I removed the door flap because my cats prefer not having it, and it was easy to remove. All in all, I would recommend it and purchase it again.