Hi Jim,
We had a 12' Porta-bote that we hauled all over. They are virtually indestructable... and unusual. Instead of pounding like a small hard dinghy or bouncing like an inflatable, they kinda "slither" over waves... it takes a little getting used to, but it works. I was told our 12' would plane with a 5 hp motor... it didn't, even with just me aboard. But, they row decent (certainly better than an inflatable) and do fold down flat, about the size of a surf board. Having said that, you still have the seats and transom to find room for, and those take up plenty of space. Once you do it a few times, the set-up is reasonably fast. They are not light weights; it took two of us to pull the boat up onto our trimaran or lift it on top of the SUV. Unless you have a big open area on your boat (we had that on our trimaran nets), you will probably want to set it up on solid ground; I can't imagine any way to set one of these up in the cockpit of a CD or CC.
The company sells lots of them; I see them all over. RVers are particularly fond of them because they fold flat and make mounts to carry them on an RV. At a quick glance, they don't look too much different from an aluminum boat, so you may not have noticed them around you.
One thing I really didn't like: the hard rubber joint on the very bottom of the boat is part of what allows it to fold. When bringing the Porta-bote up onto another boat, if that rubber part drags against the boat, it leaves a nasty skid mark that is damn hard to get off; and there is no way one or two people will just lift this boat up out of the water to bring onboard the mothership. We dealt with this by putting a rug down where the rubber would drag.
That said, they are a good dinghy in most circumstances. They do fold reasonably flat. When new, they are hard to open (they give you a notched board to facilitate opening)... I had ours close up on me when I was first starting to open it... it closed down around my calves like a shark and I fell on the dock. No injury, but it was pretty funny looking.

I got rid of the boat before we made the change to a C-Dory because I found the inflatable that we still use to be more convenient. But, if you are ever landing around sharp rocks or oyster shells, you will really appreciate this boat - it is bullet-proof.
Best wishes,
Jim B.