What am I looking for?

Let's talk about what I'm trying to find, and how I'll rate these rugs.

The biggest problem for me is robots getting stuck on the rug. This can happen at least three ways:

1. Shag or otherwise long rugs get caught in brushes
2. Light or floppy rugs can be lifted into the main brush and get stuck
3. Rug bunches up and the robot tries to drive over it, lifting one or more wheels off the ground

Another minor problem is the rug moving under the robot. I have a rug in my bathroom that never stays where I want it to; every time the robot vacuums it gets pushed into the corner.

The last important quality is that when the robot vacuums the rug, the rug ends up clean. Some textures might be hard for a robot vacuum to clean properly.

So taking all that into account, this is how I'll rate rugs.

 ⭐⭐⭐⭐⭐ - robot vacuums will never get stuck, rug will never move and will be well vacuumed

⭐⭐⭐⭐ - robot vacuums will rarely get stuck on this rug, but it may move sometimes or not be well vacuumed
⭐⭐⭐ - rug will sometimes stop robot, either through getting caught or rug bunching, but only requires lifting and replacing the robot to fix
⭐⭐ - rug often get sucked in or tangled with brushes, requiring disassembly to free it
⭐ - rug often gets sucked in or tangled with brushes, requiring rug to be cut

[0 stars] - rug will likely cause physical damage to the robot, requiring repairs

As an example, I'll use this rug that I have at my front door. My vacuum never gets stuck on it, but it sometimes get pushed around. I think it gets pretty well vacuumed unless it is pushed around. So overall I'd rate it  ⭐⭐⭐⭐.