everything that CPS said . . . but from my perspective the Delta 12-10 [and the other shorter Deltas, but 12-10 especially ] are a spectacular solution to packing a lot of desirable features into a very short, compact package, while minimizing quite a few of the ensuing compromises.
I credit Mark Hall - the unheralded original Delta designer - for coming up with this interesting approach where he wasn't afraid of going a little wider [25"] than the widest kayaks of the day, using a large block coefficient to pack volume into the other small dimensions, using short length to minimize thermo plastic stiffness shortcomings, . . .
and most especially , most especially DROPPING the cockpit rear down JUST for the cockpit region in order to maintain or achieve all of the cockpit paddler and paddle rest ergonomics that one would hope for in a much higher performance boat and popping that volume back up for the rear cargo region. And doing it all in a fairly aesthetic package.
From what I've seen, Mark was the first and did it the most completely right off the bat and all the rest were followers much later.
I could go on, but I haven't been in one, but would have no qualms with the 12-10 as a first boat because it could easily be used for multi-day trips while being a reasonable paddling kayak, while also allowing one to develop multiple self rescue approaches and all in that short, easily stored and handled package.