Let me start out by saying this boat is only for very skilled paddlers with advanced paddling/balance skills. It is very tippy and I found the seat to be very narrow for my hips (and I'm a skinny guy) and too high so as to contribute to the overall instability of the craft.
Yes, this boat is very fast and I very much wanted it to fill a niche in my boat arsenal, but I couldn't find any one aspect of the boat to fall in love with. The cockpit is very small and I can't imagine what re-entry in open water would look like as a result--especially in such a tippy craft-- so I don't see the boat being used as an ocean kayak. This small cockpit also rules out the boat as a flat water racer since it doesn't allow the legs enough range of motion. I can't see the boat being used as a downriver racer since it is relatively long, not very maneuverable, and you can't really lean it to aid in steering since the hull is round with no wings and you can't lean too many degrees without going over.
It is a beautiful boat that looks cool and goes fast so I guess if you simply want to paddle around a calm lake with it and use it to help develop balance skills that would be a good use, but certainly there are better training boat out there.
Aside from that, I don't really see a niche for this boat and perhaps that's why you just don't see many of them anymore.
Things this kayak does well is that it is solidly constructed, and lightweight (I have the carbon version), and fast, and I find it absolutely beautiful in red/black carbon fiber. I had to replace the tiller bar for the exact reasons mentioned in previous reviews, and now have gas pedals which I love, and makes the kayak quite responsive.
Big complaints are that the cockpit entrance is way too small and makes reentry an art-form. Filing down sharp edges helped a lot, but the entrance is just too small for a 6-foot paddler. I also find it very unstable and am not able to sit in it without a blade in the water even with the seat lowered -- forget messing with the GPS or eating lunch from this kayak, it can't be done. It is about equally stable in rough conditions as flat water since it is active bracing in either conditions that keeps it upright. One other complaint is that when piercing waves, the front hatch kicks most of the wave straight into your face. If this kayak were one inch wider beam with similar hull shape, much larger cockpit entrance, and slightly redesigned deck with redesigned tiller bar (like mine!), and a back rest which I have also added, the kayak would be fantastic for those who like to go fast but also enjoy sea kayaking.
I have also taken this camping and additional cargo does help stability, but there is only cargo space in the rear, so it is difficult to balance the load.
My boat is in fiberglass and REALLY heavy. It seems to be over 50lbs. The bulkheads offer a degree of safety when the inevitable capsize happens with a boat this tippy. Build quality is very high, with a smooth finish, and solid components. This is typical Nelo. Entry / exit is pretty tough, and requires a dock, because of the very tight cockpit.
I got this boat as a clearance item for a very aggressive price. Overall, it is a pretty reasonable training boat. It is very solid (a plus compared to other performance boats). Acceleration is pretty marginal, it rides wakes and waves pretty well.
The weight and small cockpit are why I knock this down to a 6. Otherwise, it would probably be an 8 or 9.
The kayak is seaworthy and is only limited by the canoeist's skill. It is probably the fastest sea kayak today. I only recommend the kayak for people with experince from racing as people with a background from whitewater and sea kayaking will probably hate it.
Other features of the boat are that its hull is very similar to the rounded hulls of racing K1s, without the noticable cheeks of sea kayaks, which puts its stability between that of a K1 trainer and racing K1, certainly not as stable as a Looksha II, for example. So taking it out in the open sea is for the brave and skillful only. Finally it also seemed heavy for a graphite boat.