I am a big fan of my Thermarest Neoair, which is very comfortable, light and packs down small. However, I find that I tend to roll off it when I am asleep. Recently I needed to buy another light weight mat for one of the family. Rather than just buy another Neoair, I did some research and discovered the Exped Synmat Ultralite .
Like the Neoair the Synmat is an inflatable, but there are significant differences. The Neoair relies on internal baffles, which prevent convection, to achieve its insulation. The Synmat is filled with Primaloft, which is laminated to the walls. This prevents the filling from migrating and allows for greater loft.
The Neoair uses a single valve for both inflation and deflation, but the Synmat has two separate one way valves. Most people inflate the Neoair by mouth. You can inflate the Synmat the same way, but moisture from your breath will eventually compromise the effectiveness of the Primaloft. Exped sell a pillow pump , which functions both as a pillow filled with expanding foam and an air pump. I decided to buy a pillow pump, which works well both as a pump and a very comfortable pillow.
There is one other important difference in construction between the Synmat and the Neoair. The inflatable tubes in the Neoair run horizontally, whilst those in the Synmat run vertically along the length of the mat. The outer tubes of the Synmat are slightly larger than the inner tubes, which makes it harder to roll off the mat.
So how do the two mats compare for sleeping on? I haven't tested either mat in really cold conditions, but both kept me warm. Note the Synmat has a slightly higher R value, so in theory should provide better insulation. Both mats require about the same effort to inflate and pack down to a very similar size. However, I did find the Synmat slightly more comfortable than the Neoair and more importantly I didn't roll off the Synmat during the night.
The Neoair feels quite flimsy compared to the Synmat, but I haven't had a problem with punctures. A nice detail is that the Synmat comes with a repair kit, whereas you have to buy one for the Neoair.
So which do I prefer? It's a very close call, I like both mats and compared to other types of sleeping mat like my old Karrimat, or self inflating mats, they are streets ahead in terms of comfort, lightness and pack size. I marginally prefer the Synmat as I find it slightly more comfortable and so far I haven't rolled off it.
Comparison of Weights, Size and Insulation.
|Synmat (medium)||183 x 52 x 7||474g||3.5|
|Neoair (regular)||183 x 51 x 6.3||396g||2.5|
Dimensions are the manufacturer's stated ones. Weights were measured on my scales and include the stuff sack.