I loved the idea of this product because I have 2 kids and one is a bit too old/big to fit comfortably in a trailer but too young for me to trust on his own in the busy streets. With this he could ride his own bike at times and connect to mine for the longer rides, all while his sister could be in her reat child seat.
In practice, this product could still use some improvement. Mostly, this thing is HEAVY! Add the weight of my second child in her child seat and I'm pretty sure my rear tire won't last for long at all and the idea of a blow out with 2 small kids is frightening. Also, with the extra weight added on, this caterpillar bike becomes a beast when trying to go uphill. When not attached to the second bike, it's still heavy enough that I have issues with maneuvering my back tire around. Plus it rattles like crazy when not attached to a second bike.
Like I said before, I love the concept of this product. But after a few short rides, I've realized that I won't be able to take this thing for any longer rides than I would already let my son go on his own because the burden of riding it is a bit much for me. Kind of a huge letdown with this big of an investment. :(