I've been using a pair of Neoairs for myself and SHMBO, mainly for bike rallys (10 per year) plus camping since they were first released and available in shops. Before that I was using a pair of Exped Airmats, before that a pair of Thermarest Prolite 3's. I also have an Exped Downmat 7 DLX which is what I tend to use solo (too tight to buy a 2nd for SHMBO) and 4 Multimats (one an original Karrimat expedition). So I have quite a bit of experience with them all and can give a proper comparison.
For anyone who doesn't know how a Neoair works, they are ligtweight inflatable mats just under 2" thick which, unlike traditional Thermarests, have no foam insulation inside. Instead, to stop them getting cold like traditional lilos, they have a series of internal baffles to stop cold air circulating. Additionally these baffles are coated with reflectorised material to reflect body heat.
The major feature of the Neoairs that puts them in their own class is the packed size. The regular size packs down slightly smaller than a 32oz wide mouth Nalgene bottle, which volume wise is massively less than any of my filled mats and also noticable smaller than the Exped Airmats. As I carry camping gear for 2 on 1 bike this is a major plus, and on any camping trip sleeping gear tends to account for a large amount of the pack space. Even if I wanted to buy SHMBO an Exped Downmat I wouldn't, as when carrying for 2 the Neoairs are just superior.
Warmth wise they are advertised as 3 season but they are very nice and warm. They have reflectorised baffles inside which a) stop heat circulating and b) reflect body heat back. If you lie on them inside without a bag you can feel the heat coming back up. In my opinion they are noticably warmer then the Thermarest Prolite 3's. The Airmats are essentially lilos and have no insulation so I only use on top of a closed cell mat. Nothing touches the Exped Downmat for wamth. I would also point out that SHMBO has given the Neoairs a big thumbs up from first use and all the way through the year. She usually sleeps cold and regularly informs of of this during trips
Comfort wise they also get a big thumbs up. I've generally found airbeds to be uncomfortable on the back, but these feel different. My gut feeling is that all those baffles give more structure to the mat limiting movement between the top and bottom. The air chambers also run laterally side to side rather than most mats which run top to bottom. Whatever the mechanics it seems to work. At almost 2 inches thick they are also more comfortable than the Prolites. As stated, possibly due to the baffles I find the neoairs more comfortable then the exped airmats which are about twice the thickness. Personally I think they may even be more comfortable than the Exped Downmat, although it's a close thing and due to the thickness of the Downmat it can cope with greater uneveness in the ground.
Durability is the only questionmark in my mind. I've been using these for over a year now and no sign of wear, damage or leaks. They are from the "fast and light" series though and the fabric does feel gossamer thin. I wouldn't use these to sleep on the forest floor or sharp rocks unprotected, but then I wouldn't use any inflatable mat without a closed cell mat or come other protection underneath.
They have always shipped with a grey stuffsack. There is an additional stuffsack accessory available in a matching material. They don't ship with a puncture repair kit. However as most repair kits state 24 hour drying time if you get a leak in the field the damage is done.
They don't burst in hot weather. There is a noticable expansion and contraction of air between noon and night, as there is with all of my other inflatable mats. Personally when I set up camp I inflate them but don't blow them up tight. Then when I turn in I add a final lung of air to get the pressure how I want. When I get up in the morning I let a squirt out (of the mat) to allow expansion. I don't know what would happen if I blew them up to 30psi in the cold of night and then left them the following day in the scoching sun, but it's a bit of a non-issue as I don't: I take care of my kit and do the same with all of my inflatable mats.
In summary, yes they are very very good, especially if you are wanting to travel light or space is at a premium. However if you need very rugged kit for hard use, maybe not first choice.