I bought one of these and it's two man brother for use on Lake Annecy in France, where it works beautifully. It is not a rigid kayak and so does not handle as well as they would (particularly the 2 man version where involuntary spins occur if you paddle too hard at the back - but that normally just adds to the kids fun!)
Like the other reviewer I would not recommend for sea use, but it handles the wakes and small waves on the lake competently. This big plus for us is it inflates and deflates very quickly and packs up into one bag which can be carried to and from your car. No having to fit roof racks and manoeuvre the kayaks onto the roof, just fold them up and sling them into the boot. This is a great, convenient and cost effective way to have fun on the water, we take ours out across the lake and paddle for hours. They are pretty tough too, no leaks after 4 years of use.
if you are a serious paddler you would not be considering this product, but if you want to have some fun with your family in suitable waters, you won't go wrong here. But buy yourself some better paddles if you are going to paddle for a long time.