The Exped Megamat Duo is one of several mattresses in this review that are queen size and, therefore, perfect for two people. Keep in mind, these mattresses are not only for couples, as a single person can happily starfish across the whole thing in lounging fashion, but they are designed with two people in mind. The Megamat Duo is different from its competition in that it is a self-inflating air mattress, rather than an air bed.
This means it is not nearly as thick as these air beds but provides greater warmth and comfort due to its interior foam cushioning, something they lack. Where the air beds are superior is when it comes to ease of use (they are easier to inflate and especially deflate and pack up) and packed size (the Duo has the largest packed size in the review). The air beds also come at a much lower price, but will "cost" you a lot in comfort, warmth, and versatility.
Performance Comparison

The Megamat Duo perfectly fits in the back of a pickup truck, making for a wonderful night's sleep in a wonderful location!
Photo: Chris McNamara
Comfort
The foam that fills this mattress serves many fine purposes. Not only does it insulate from the ground, but it pads as well, especially at those pressure points, like the hips, feet, and shoulders, where your weight sinks deeper into the pad. It also evens out the cushioning under your body, dampening the air mattress effect. We felt that the most comfortable way to use this pad was much less inflated than other air mattresses. This way, your body is equally supported by the air and the foam, and more importantly, the mattress wasn't so full of air that when one part of your body sinks into the pad, the other parts would naturally rise with the displacement. Luckily, the inflate valve system with a rubber flap to impede air from escaping while inflating allows you to blow this thing up as rigid as you want it. You can then let air escape as you lie on it till it feels just right.
Additionally, the face fabric is smooth and comfortable to the touch, without a hint of rubbery, nylon-y, or plastic-y feel. Compared to the air bed alternatives, this mattress is super deluxe and hardly in the same universe in terms of comfort. This one will absorb the movement of the other person without disturbing you, and we gave it the highest possible score in this metric.

Photo: Brandon Lampley
Ease of Use
While it isn't all that hard to inflate and deflate this beast, it does take the proper strategy and a bit of time. All of the same tactics and inconveniences of the MegaMat 10 apply here, but double the size means double the work.

The Duo 10 expands with the inflate valve left open.
Photo: Jenna Ammerman
For inflation, it is best to open the inflate valve, roll out the mattress, and let it inhale air for a while as the foam cushioning inside expands. Propping the inflate valve open with the supplied toggle helps speed up this process. You will want to allow it to inflate for at least ten minutes, preferably more. When the pad is brand new or has been stored really tightly, it's helpful to let it self-inflate for up to an hour to open up the cells to air.

The mini-pump in action. Attach one end to the inflate valve, and then repeatedly step on the inflated balloon, like you are trying to crush an aluminum can. While this is a sort of a cool design that doesn't require using your lungs or an external power source, you will need to stomp on this balloon about 300 times to fill one of these mattresses.
Photo: Elizabeth Riley
Now, inflate it the rest of the way with the provided "mini-pump," a small, whoopee cushion-like device that works as a tiny hand or foot pump. While we like how small this pump compresses, and the fact that it exists at all, saving us the effort of manually inflating it with our own hot air, it still takes some patience and the willingness to stomp on a whoopee cushion a few hundred times to fully inflate this mattress. An accessory pump that plugs into your car or is battery powered will save a lot of time.

MegaMat's larger, new, and improved deflation valve.
Photo: Jenna Ammerman
To deflate the Duo, the technique we found most convenient is to open the deflate valve, fold the mattress over, and lie on top of it, forcing the air out. It's helpful to have a second person remain on the pad while one person rolls it up. This process takes about two minutes. The less you deflate the pad, the faster it will inflate the next go-around.

After fully wrestling the air out of the Duo mattress, all that remains is to fold it in half and roll it up. Constant pressure is needed in order to keep the mattress tightly rolled so it will fit in the stuff sack.
Photo: Elizabeth Riley

Exped's new stuff sack is makes it easy to protect and store this mattress.
Photo: Jenna Ammerman
Warmth
The ample foam cushioning that is found inside this mattress helps it provide an R-value of 8.1, a very high rating. R-value is a measurement of how well any given material, or combination of materials, impedes heat (or cold) transfer. The higher the number, the better a job it does. The ground, or metal frame of a vehicle, that is underneath your car camping mattress is always going to be colder than you are, so a critical function of your mattress is to insulate you from absorbing that cold. This mattress does an excellent job at that task, definitely the highest-scoring double model in our test.
Versatility
We could only give the Megamat Duo a middling score for versatility. This mattress is gigantic when packed down, and is very heavy as well, ensuring that you won't end up carrying it anywhere (it is as big as a backpack!). It doesn't separate into two mattresses for individual use, and also can't be broken into parts like some other camping mattresses. This bed needs to be used near, or inside of, the car, limiting its versatility. However, it can be used in any season due to its great insulation, something that cannot be said of the air bed alternatives.

The thicknesses of the four mattresses in this review designed for two people. From bottom to top: The Alps Mountaineering Rechargeable Air Bed, REI Relax Airbed, Lightspeed 2-person, and Exped Megamat Duo. Of these four, the top one is the only one with built-in foam for cushioning and warmth purposes.
Photo: Elizabeth Riley
Packed Size
This is the single largest packed mattress we tested, by a long shot. That said, the stuff sack is large and very easy to get the pad into. Once it's 90% deflated, you can get it into the bag, but you will need a large space to store it when it is not in use.

There is ample room for the MegaMat Duo 10 in the improved stuff sack. This minimizes the time spent perfectly deflating and rolling up the mattress and makes packing up much easier.
Photo: Jenna Ammerman
Value
The Exped Duo is an expensive purchase, over three times as much as an air bed will cost you. Since we think that it is the very best mattress you can buy for two people and is still quite a bit cheaper than buying two single person mattresses of the same quality, it is a good value.

Hard to beat this view from the back of the truck. Looking out from the hills of the Eastern Sierra.
Photo: Chris McNamara
Conclusion
Compared to the other two-person options available today, namely inflatable air beds, even those that are insulated, this mattress is light years more comfortable. If you need a mattress for two people, this is, without a doubt, the one we would recommend.

Photo: Brandon Lampley