I think this is THE best mattress on the market for paddle camping, bar none. It offers unbeatable comfort in a weight and packed size that are perfectly acceptable for a canoe or kayak. The LXW fits easily in my kayak hatch but I've ordered the narrower MW to use on the Helinox Cot One.
When I say the comfort is unbeatable, I mean I slept on it for 6 months at home and was very comfortable. It's a whopping 4.7" thick. The only way to get that much thickness in an air mattress is something like an Intex. So why would you spend four times the price on the Exped Synmat Mega 12? BECAUSE IT'S INSULATED. You can use this in the winter. It's rated to minus 4.
What makes the comfort besides the thickness: the large tubes that you barely feel, larger exterior tubes to keep you on the mattress, box sides, and soft material.
The overall best paddle camping mattress is the Synmat Mega 12 MW. Check these specs:
24 x 73 | 2lbs 8 oz | Packed size 6 x 11
Unless you're counting grams because you do long portages, this is a great size and weight for so much comfort. If you're a larger person, get the LXW---it's only a bit larger packed size.
Expensive, yes. Well worth the price if you camp a lot and value sleeping comfort. I own three Expeds and a fourth is on the way. I've never had a single quality problem and I've slept on these mattresses literally hundreds of nights.