What I Like About the Rope Perch
My Knot-a-Rope perch has stood up very well to life with my three rats. The rats have used their rope perch mostly as a perch - an extra place to sit and balance especially when looking for attention and treats at the front of the cage. It is easily attached to the cage bars - the ends have slotted plastic pieces that fit over a bar, and a plastic cap that twists over the ends on the outside of the cage bars fixes the perch very securely in place.
What I Don't Like
The perch is actually quite stiff; between the stiffness and the length there were limited locations in the cage where the rope would fit. You may find it difficult to position such a perch around your existing cage layout / accessories. I was also hoping the rats would use it more as a climbing type toy.
My rats have not chewed on the perch at all, as far as I can tell. However, if your pet chewed on the rope, it would have to be discarded fairly quickly as you wouldn't want to take a chance that your pet would swallow the smaller threads which are wound together to create the larger rope.
Bottom Line
A good thick cotton rope can sometimes make a good addition to a pet rat cage, or other pet rodent's cage, though they may not make great use of it. Watch that your pet cannot fall a long way from such a rope perch / toy, and make sure your pet is not shredding the rope (and potentially swallowing it).