So far the yak is everything I have read about it. With one exception. For a big man, the coaming is totally useless. In fact it was too confining for even my wife.
Also, what Oaarsman said about the footwells being VERY tight is an understatement. Somehow OK missed the obvious... bigger people usually have bigger feet. Kind of a dumb oversight.
Not only do the actual foot holes, themselves, grow smaller as they go forward from the seat, but the front part of the cockpit also narrows extremely abruptly, truly cramming bigger feet into about half the space needed. I'm learning to live with it, but it seems that this design fault was completely unnecessary.
The honest room, front to back, is fantastic. With my 36" inseam, I can lay my legs completely flat on the floor of the cockpit, and there's still a few inches left. (If only there was someplace to put my feet way up there.)
All in all, I give it a 7 also, and it is all due to the lack of foot room. Otherwise, it would be at least a 9.
I had full expedition gear: tent, sleeping pad and bag, stove, lantern, fuel, cooking gear, 8 gallons of water (carried in dormedaries) and food for two weeks with room to spare and still extremely stable. With a Primex sailing rig mounted on the center hump between my knees she did a great beam reach and run. Rudder works easily and effectively. As mentioned earlier, foot wells and pedals stink. Hope that is remedies in her re-design. I highly recommend her.
Anyway, I've tested many boats in waves and own five of them (various lengths and purposes), but the first time I rode some 2-footers in the Manta, I was in love. It is a substantial boat and rides waves like a dream. Somehow, it minimizes them. Since I'm not getting thrown around at all, the Manta allows me to hold decent speed in waves, too.
I need a wide boat for stability since I lack trunk control, and the Manta offers plenty of it. Any other boat this wide tends to toss me around in waves so that I can't paddle very effectively. Also, I can't figure out why the Manta glides so easily for its width, but my hat is off to Ocean Kayak. I was greatly disappointed to hear that they're not making the Manta in 2002.
The boat turns remarkably well for a sixteen footer, but if you'll be using it in a 30 mph crosswind, I recommend a rudder. I'm going to skeg mine since I can't use foot pedals. I have the coaming to turn it into a sit-inside, and I love it. I put in the scupper plugs and stay dry and toasty in 40 degree weather. The only reason I don't give this boat a 10 is because it's a heavy tub when it comes to loading. Due to the weight, it also doesn't accelerate fast, but who cares about acceleration on a long trip? As a bonus, the boat just looks great!
There is an inordinate amount of storage below the front and rear Scupper Pro type hatches. I'm sure you could put all your scuba gear and a weeks worth of camping gear below with ease! I was even able to get my fully outfitted tank/bc/reg unit into the rear hatch, although I did have to tuck the hoses and console in a bit to make it easier.
The Manta is as fast as it looks... I was moving along more than 10 feet with each light paddle stroke I made! I took the Manta out around the outer jetty at Channel Islands Harbor on a rough and windy day. The nearly three foot chop slowed the boat considerably but I felt so comfortable with the seaworthiness of the boat that it didn't bother me at all to be out there in only shorts and a T-shirt in 62 degree water temperature. I was also glad to note that the Manta did not exhibit a leeward helm characteristic (bow blowing downwind in a crosswind) that I have seen in so many other longer kayaks.
I turned the Manta toward the beach and tried my hand at catching about a dozen small waves with it. OK, so it is too long to actually make any maneuvers on the wave front, but, it is the first kayak I ever surfed on which you could catch even a small wave LONG before it ever crested or broke. The Manta "wings" helped to keep the pointed bow from diving and the Manta handled much better than expected in a broach (washing in sideways on the wave).
Did I mention how stable this kayak is? I think I leaned this kayak over farther than any other kayak to date without feeling like it was going to go over on me! Also, this kayak simply feels sturdy and durable. OK, so that is probably due to the 70+ pounds it weighs, but it is still impressive. I'm looking forward to getting a coaming for mine and trying sit-inside winter paddling for the first time!
Note: I would have subtracted a point for two possible reasons: It is on the heavy side for a single-seater, and the hatches are not as easy to access as a scuba diver as, say, the Scupper Pro, But...., there is just too much else I like about it, especially for the larger paddler. The weight isn't that bad for the 16 foot length of the Manta and the speed is excellent!. And, even though you have to reach for them, those hatches cover more cargo space than any diver is likely to ever need, so I have to give it a solid 10!