We used to use these a lot at the shelter. They really give the dog a chance to roam and explore without the person having to go all over to. We are on a dead end street, so they provided an excellent opportunity to give a dog a little more exercise and freedom than a standard 6' leash provides. The big downfall to these is that a lot of people really don't understand how they work and in situations where people don't have a tight grip or understand how to "stop" the lead from going out further, they become a hazardous thing. Because we have such a huge variety of people coming through the shelter and walking dogs, we discontinued using these because of that issue.

Pros: lots of different lengths, allows for more exercise

Cons: works poorly when you don't know how to use it

I just love using my retractable leashes for my 2 dogs. It gives them so much more freedom when walking. They can meander to tantalizing scents and still walk on the path with me. I wish my first leash had lasted longer than 2 years. The gears stopped working the the leash would not retract. I did purchase another one though. The concept is just too appealing.

Pros: Gives dog more freedom

Cons: Gears wore out

I like this one cuz its simple this is the one I recommend. I don't like the color but I'm sure you can find a similar model in a different color.
I love the Flexi leashes they are my favorite for exercising dogs. And the dogs love it too! Great for teaching recalls!
Allows freedom to run and play on down time. WARNING:DO NOT GET TANGLED IN IT! AMPUTATION MAY OCCUR!

Pros: It can let your dog run around without you running with them

Cons: It can rip off a finger if it gets wound around it

I have used this leash for 8 months with my dog, an active pomeranian. It retracts and locks easily and quickly. It seems very durable and has served its purpose well.

Pros: Locks and retracts easily, very strong, choice of colors

Cons: None noted

We use this to play out side, go potty and at the beach but when we walk we need to use another one with more control.

Pros: It alows for her to play.

Cons: Not much control when you are training.