I've always been mostly non-picky with mattresses. I've always slept great in hotel beds, which I would assume are somewhat "neutral." However I immediately had issues with my Casper. It was surprisingly firm, and nothing like the "cloud" that I was told it would be. I ended up having back pain and after a significant time trying it, I returned it. It took me over a year to get rid of the back pain after getting a much softer mattress from Mattress Firm.
Obviously plenty of people do like this mattress. But it's important to realize that it truly is firm, and if you're not ready for that, then it will feel much more like sleeping on a rock than a cloud.
[This review was collected as part of a promotion.] My guests have been very happy with my Casper full-size mattress. Delivered on time with frequent notifications of the delivery. Slept two adults comfortably, one a back sleeper and the other a side sleeper. The foundation was easy to put together and no odor from the mattress.
I needed a new mattress, so I saved up and got a Casper. The Casper is the most uncomfortable mattress I have ever slept on. Almost immediately I was experiencing pain but thought maybe I needed to get adjusted to the new mattress? I wouldn't call myself a "picky" sleeper, I can sleep on pretty much anything without issue. But not this mattress. I am a back and side sleeper and I have considerable lower back pain since getting this mattress but can't return it. Oh well, live and learn to not take people's positive online reviews too serious, I guess?