I voted other because we have six cats and eight boxes, so I couldn't pick just one.
We have four upstairs and four downstairs: of those, 2 are Litter Robots and one of each of those is on each floor.
We have one in the guest bedroom - that's only for when Gary's mom stays with us. They like to sleep under the bed in there, so we didn't want anyone to get trapped in there when she closed the door for the night because she sleeps for like 12 hours. When she's here we put water and food in there too.
We have one in the upstairs hallway and two in the "cat room." (A third bedroom). One of those is a Litter Robot.
The living room/dining room are one giant room (and we don't have a dining table - the eating area is in the kitchen). So we have two in there - kind of at each end of the room.
The other two are next to each other: one of those is the other Litter Robot. They're in the short hallway that goes to the powder room.