Anyone tried the purple mattress?

The purple mattress is $400 off at my local Costco right now. I’ve always wanted one, and I sat on the little rectangular sample today and it was so comfortable. I have a bad back and have a coolive hybrid mattress right now, i’ve had it for a few years and like it, but it’s not AMAZING. Is the purple mattress as good as people say it is? Or is my conviction that every mattress is practically the same if it’s a similar material? ie if i get another hybrid mattress it will essentially be the same. I want to get an amazing mattress that I will always be comfortable on and is comfortable for my back. Is that the purple mattress? If so I need to jump on it while it’s $400 off.

Edit: thank you everyone for the great advice!!! looks like I’ll be going to the mattress store to lay on some mattresses. Everyone brought up a great point how if I have a hybrid now, I should stick with it especially if I need support for back pain. I also am going to try the Kirkland Stearns & Foster mattress and the Casper to see which one I like the best. Unfortunately I won’t be able to cash in on the $400 off because it’s not the hybrid, it’s just the grid + foam mattress which most have said doesn’t have have as much support and it doesn’t seem to last as long.