We have had this boat on the Sea of Cortez for 8 months and we like it very much. It's true that the 16 has some unique features, so it's important to make sure that you like them. We, too, bought ours "on approval" from REI as the only way to get to see one; we had paddled a 17 and an 18 elsewhere and liked them both.
Hatches are the most distinctive feature, and apparently Delta is still tinkering with them -- I have seen a recent review of an example without the rear day-hatch. It was hard to reach, at least to re-close, at least as ours came rigged, but maybe that's what a paddling partner is for. Agreed that the pod makes efficient packing difficult, but that's the trade-off for possible convenience.
We have had no trouble at all with leaks, and the other Deltas we have seen were also dry. Our "knobs" work fine though they are fussy and not attractive. One should be aware that the boat as delivered will not look like the one in the picture.
The forward day hatch is large enough to hold quite a bit of stuff, without getting in the way in the cockpit, at least underway. It has not hindered us during wet exits, but one may want to consider how the pod could affect re-entry.
The office-chair style seat is wonderfully adjustable but not well padded. I check periodically to make sure that the two essential knobs are not coming loose. The height adjustment is "quantized," unlike some other slot-type models which might not stay put so long but might give you some warning before shedding parts. I kind of like the cord-type adjustment for both the seat back and the skeg as being more nautical (i.e., replaceable without fancy hardware) than some. This is even more true of the carry handles -- our other boat, an Eddyline Fathom, has spring-loaded retractable toggles that can't drag in the water; but when I need to swim my boat, or just tie it down on my car top, the handles I want are the ones on the 16.
Our 16 keeps up fine with our Fathom, probably doesn't hold quite so much stuff but holds some things that the Fathom won't -- because of the big hatch covers. The Delta is more fun to maneuver. I'm 6 feet, 160 lbs, my wife is shorter; people bigger than us will want to make sure they have room in the cockpit, maybe particularly for feet including footgear.
We only considered ABS boats. I like the seats and the pedal adjustments in the Perceptions, and like I say we bought a Fathom too. But I don't like any of them better than the 16. That 9 rating from me is probably as good as it gets.I recently had the opportunity to test drive a Delta 16. Well, actually, I bought one from REI during their 15% off boat sale. It was a web-only item. When I picked it up, I noticed striations all around the heat/chemical seal of the rear bulkhead. I thought there was some small chance that this was normal, and after the store manager reassured me about their return policy, I took it home. Eventually, I put several inches of water in the cockpit, and was able to see it leaking through to the rear compartment. Careful inspection revealed that some of those striations were actually open cracks. So, I had paddled the boat a few times before returning it. My test drive cost me $100 in travel expenses. Though I decided it was not ideal for my needs, I'm sure it would be great for some paddlers.
Obviously, a primary reason to buy a Delta is the thermoformed plastic: tough, slick, attractive, light weight, UV resistant, fairly rigid, and less expensive and less heavy than fiberglass. At 22 inches wide, this is one of Delta's narrower and ostensibly more efficient offerings.
I'm 5'9", 135 lb male, 52. I was only able to test paddle in calm water. Stability was fine. I found the maneuverability and edging to be quite good. Hull efficiency did not meet my expectations. While it would cruise along nicely at 4.6 MPH, 5 MPH took so much effort as to not be practical (in contrast, I get more than another 1/2 MPH from my 23 inch wide CLC Shearwater 16). I have to wonder if the concave sides and bottom facets add drag to the design. The full stems may be a factor here, too. I didn't get a chance to do anything meaningful with the skeg. It deployed easily. With just a jam cleat for the rope, incremental adjustment was not convenient.
The cockpit was not bad, if a bit larger than necessary. The sliding seat is a nice feature. I adjusted the position until my thighs fell nicely on the braces. I could have used some side padding. I do like having some room behind the seat for water and other things. The seat was not right for my bum, but, I have no padding, and factory seats generally don't work well. The seat pad had what appeared to be a drain area at the bottom -- but, there was no hole through the seat pan to allow water to escape! The seat back can be adjusted vertically while out of the boat, and the bungee'd hinge worked nicely. I found the single cord for seat back support and adjustment to be skimpy, and considered that the approx. 12-inch free end beyond the jam cleat might be an annoyance or safety hazard. And, shortening the cord would impair adjustability.
This is the only model where Delta has opted to include a front day hatch, and lock knobs on all the hatches. The front day hatch is a nice convenience. It is smoothly rounded on the underside of the deck, and does not at all interfere with your feet. The lock knobs work, but, they also leak. The knobs don't have their own seals, so, for example, the front day hatch would get a little water in it from paddle splashes. All of the hatch rims were nicely finished. Where my last thermoformed boat (a Perception) had the hatch edge pointed outward, Delta went to the trouble of turning the edges inward, to hide them and add rigidity. The main hatches are quite large. I was able to get the halves of a 230cm paddle into either hatch, as a test. The rear day hatch is a pod suspended under the deck. It seemed a little small. I didn't mind open space beside the pod, in the main rear compartment, but, the approx. 1 inch below it seemed wasted. Each hatch had bungees crossing over it, with hooks to quickly snap them in place. But, the combination of knob locks and bungees was a bit of a bother, and the bungees were so tight as to limit what other gear they could hold.