Thanks for expanding the data base and adding criteria.
I am going to address the "problem child" for all these comparisons, which we all know is the Klymit pad. It defies comparison on the normal scales.
These are the reasons:
#1) We have test data that the "loft pockets" actually DO show R-value results higher than the body of the pad, and the company designed this into the system and patented it, which shows that they know about it. Since we don't see this in other pads, that makes comparisons difficult. The loft pockets showed R2.8, while the main body of the pad showed between R2.0 and R2.2, depending on how much it was pumped up. Adding the loft of the sleeping bag down insulation material in these Loft Pockets has, as yet, an undetermined additional benefit of insulation under the user, which permits the recovery of some of the sleeping bag lofting ability which otherwise is not seen at all in competing pads.
#2) The Klymit pads have a unique construction which permits them to be used INSIDE the sleeping bag. When the pad is inside the sleeping bag, it is not subjected to the outside air temperatures, or even the direct contact with the ground. This nearly eliminates convective losses, and reduces conductive losses to the ground enough to be significant. The pad operates in the heated environment of the sleeping bag, which sets it apart from all others. Other pads do not offer this option, and therefore they are all subject to serious losses in insulation performance from convection and conduction. This has the potential to GREATLY improve the cold weather performance of the pad, above and beyond any R-value rating that may be taken out of context with the pad in a stand-alone test.
And using the pad inside the bag prevents the pad from slipping out from under the bag when the user moves around. If the pad slips out from under the user with a normal pad, it could end up not being under the user at all, giving a zero R-value until the user wakes up freezing cold.
#3)When the pad is used OUTSIDE the sleeping bag, as some wish to do, it has a thinner profile exposed to the outside air, and therefore has less issue with convection losses occurring from air movement inside the pad body tubes. Thicker pads suffer more from convective losses from this air movement. Conduction losses to the outside air may also be reduced by the smaller wall area exposed to the cold outside air. However, the NeoAir pads 'may' suffer less than normal design pads from convective losses due to their internal baffle structure, and it would seem to be evident from their thermal performance rating in the new line-up. The baffles in the NeoAir perform the function of the thinner tube profile in terms of reducing convection losses by controlling unwanted air movement.
#4) The thinner profile of the Klymit pads is not necessarily "anti-comfort" as perceived by some. The Klymit pads are heavy-duty construction and can be pumped-up harder than other pads can. This gives a firmer base that 'might' be preferable to some, and could offer lower likelihood of "bottoming out" on the ground than might first be suspected from the thinner profile. At a lesser-than-full pump, the Klymit pads still offer a good comfort level(by my own personal test), which is surprisingly good for their thin profile.
#5) On the potential negative side, the Klymit pads are dependent on body size and shape fitting into their expected range for best use of this pad. This is a deal-breaker for those who do not fit, and there is nothing they can really do about it, even if they wanted to use the Klymit pad.
Another negative pointed out in the BPL test is that water in the floor or on the groundsheet can contact the sleeping bag material if the water intrusion moves to anywhere in the skeletonized areas of the Klymit pad.
#6) The flip side of #5 is that the Klymit pads are the lightest inflatable pads on the market for their respective sizes, and the skeletonized structure and body-mapping are part of what permit the light weight to be realized.
#7) As you mentioned, the Klymit pad(particularly the X-Lite) packs very very small, and I don't know of any other pad that can compete with the packed size.
IMO, these Klymit pads are in a class by themselves, because their design and features are so different than all the other pads. It makes comparisons and categorizations very difficult when the Klymit pads are included.