This double lead in perfect for a pair of older or generally well-behaved dogs. When I got my second dog I made a contraption of sorts to walk them using one hand, but it was cumbersome and the double lead is simply a better answer.
If your dog needs a "little privacy" while out, this may not be the answer.

Pros: Second hand free to carry the poop bag

Cons: Dogs are very close together

This is a great idea, but you would have to train your dogs properly to walk with this type of leash, so they do not get tangled. Might be an issue if one of the dogs smells something good on the opposite side of the road.

Pros: control

Cons: control

This is a great walking leash. Nice to only have to hold one handle. Looks very cute with two poms on the end, even funnier when we walk the bigger dog with one of the poms. The rarely tangle

Pros: looks cute with two poms on the end

Cons: na

I have 4 Rottweilers and walking them was a pain, they would go in all different directions and the leads were getting tangled.
I saw this at Petco and thought I would try it. I put Max and Magunda together and Bear and Precious on the other one and it worked well. The dogs have to stay together so it stopped the wandering and you only have 2 leads in your hands instead of 4

Pros: Attach 2 dogs to a single leash, keeps them from wandering

Cons: none

i bought this leash a couple of months ago because my family got a new dog and after months of getting tangled up in two retractable leashes, i was going crazy. it works great. you can attach the double leash to a retractable leash and its easy to keep the dogs from getting tangled. definetly for someone with more then one dog, who hates getting tangled.

Pros: can walk more then one dog, on one leash

Cons: the leash isn't retractable