It's a scam.
I was almost suckered into purchasing one of these, but I did some research. If you look at the 'reviews' on their website, 99% of them are written by bots. They use almost exactly the same language in all of them. Even the 4,3,2 plus 1 star reviews are also bots.
No human on the internet types like that. They all read as if they were written by an AI bot with a thesaurus. Seriously, use Ctrl F and search 'comfortable and supportive' 'game-changer' 'nirvana of slumber' and you'll see the same phrase repeated 3 times on each page.
All the reviews were drip-fed in at specific times, it looks really suspicious.
If you look at their amazon seller feedback page, you'll notice that they've been abusing the 'strikethrough system' in order to erase any negative reviews. The negative reviews are still there, but they don't count towards the seller rating because they forced amazon to erase them.
While there are some youtube videos of happy customers, the majority of them were uploaded by Suilong, not independent people. The remaining ones that were uploaded by independent people were all sent the mattress by the company for free. No one in these videos purchased them independently. This means that the company are sending out nice mattresses to a few people in exchange for publicity, but the average person who buys one direct reports it either not arriving, or being very different when it does arrive. The amazon reviews are similar.
Suilong then protects themselves by telling customers 'you can't return it unless you put it in the box again' which is physically impossible. Therefore, no one can ever return their fake mattress.
It's a clever scam, it almost got me.