I am pretty happy with my Helix Sunset Lux mattress. The only thing preventing me from giving it five stars is the cooling topper that we paid additional for. 

Unfortunately, it does a very poor job of keeping the mattress feeling cool. I think it may make it worse as the topper seems to retain heat, causing me to sweat at night. The topper only stays cool for about 20 seconds. 

Everything else about the mattress is great. Easy to setup, construction seems to be solid. Balance could be a little better, but we did opt for the softest mattress. Probably could have used the medium firmness.