We have a Casper mattress that's about a year old - not the Wave, I thought that one was too firm, and we're happy with it, actually them. We have two twins because we have twin motorized platforms for adjusting the mattress angles (I didn't want to be forced to be at the same position as DH if I didn't want to, this way we have options, plus those things weigh a ton, they are a nightmare to move and a king sized one would be impossible). I was happy to find a showroom in Denver to go check it out, because I really dislike ordering big things that I can't see/touch in person. DH used to wake up with back pain for years, going to the chiropractor on a regular basis, and since we got the Casper he hasn't had back pain. I did order a cushy mattress pad off
Amazon to put on top of the Casper because I like that pillowtop feeling. After a year, the mattress is starting to seem more soft, especially in the middle. That kind of makes me wonder about its longevity over the years but it's good enough so far.