The commercial describes how it works:
"Just turn on the water and watch this mini-hose grow, and grow and grow to maximum length! Turn off the water, and it goes right back to its mini-size!"
In our test the hose expanded, as promised, as the water flowed to the nozzle. With the water turned off the hose contracted back to its original size. As for actually using the hose to water the garden, we found the connection at the nozzle leaked quite a bit. Despite tightening the connection and adjusting the washer, it was rather messy.
Drips aside, Pocket Hose worked and our tester found it to be esthetically more desirable than it's heavier, more cumbersome counterparts. One potential negative is the plastic connector parts and how long they'd last before breaking. Another negative for some people is you're supposed to disconnect the pocket hose and store it after each use to prolong its life, and you can't use it for pressure washing.
Bottom line, Pocket Hose can't replace your traditional hose for everything, but it does work. On a scale of 1 to 4, our tester gave it a 2.5 to 3.