I do not like retractable leashes. The point is not the speed of retraction, the point is that the leash is constantly taut and the dog is constantly taut. Plus you cannot see them, as we can all attest to on MUPs as cyclists. A loose dog on a loose leash is infinitely more relaxed than one on the end of a tight rope.

Dog opinions can get heated, so that's all I'll say about it. Back to bikes.