If you liked the original Helinox Cot One, you might like the Cot One convertible even better. Its main advantage is that you can use it for paddle camping (6.7" high) in a 2P or 3P tent and car camping with a 4P tent or larger with the extra leg set, which makes it 15" high. When you're paying this much for a cot you don't want to have to buy two cots for two uses. Problem solved with the Convertible! Like the original Cot One, the Convertible is lightweight, easy to assemble, comfortable, and the packed size is small. It fits 26" Exped mattresses very well (I recommend the Synmat 3D-7). The leg set (12 legs) is very small and weighs just 1 lb. The legs are easier to assemble (1 minute) and stronger than you might think---the cot is very stable with the legs.
I have to take one star off for the exorbitant price. This is a cot for the rich and the desperate for ultimate comfort. There are now Chinese knockoffs of the Cot One, but not of the Convertible. Your two best choices for a 15" cot that is reasonably lightweight are the Convertible and the Camptime Roll-a-Cot. The latter is 1/3 the price, just as comfortable, but weighs 10 lbs, takes longer to assemble, and is quite a bit larger when packed. Still, the Roll-a-Cot is a very good choice for car camping, possibly canoe camping at a stretch, without portages.
You can put this together in about three minutes and take it apart and stowe in one minute. It has a very taught surface. It easily holds my weight and feels sturdy when I turn over.
I wish it were higher than 6". The taller Helinox cots have gotten absurdly expensive so I drew the line at the Cot One. You need a mattress with all cots. I've used the REI Campbed 3.5 and the Exped Synmat 7 with this cot. Both are great.
I give this cot a 10 in all ways except price, but if you camp a lot you won't regret buying it.