I wanted to come back and report on our experience with our king size Flexus Posture Sense mattress. We’ve had our mattress now for a few months. We ordered soon after my last post in October. It is really HEAVY – and when they sent it out, they only sent one guy (apparently another delivery guy was out sick). So if we wanted it and didn’t want to keep waiting, Jim had to help him get it upstairs and hurt his back a little. So that was a bit frustrating. If we’d had to pay for delivery in the first place, we would have asked for money back.
I know this is really a subjective thing to say – but the materials just make it feel like a good quality bed (as opposed to the Sealy that we got rid of – love Costco’s return policy!). We already had a latex topper with a low ILD (19 I think?) that we added right away to make it just a bit softer – we’d tried a topper on the mattress in the showroom and liked it. After a month or so though, we decided that our Arizona Mattress latex topper didn’t add enough softness/pressure relief, so we added a 5lb memory foam topper from Costco – and the bed is really pretty wonderful now! I hardly shift all night – no more turning around and over to try and get comfortable. The memory foam still smells a bit (I’m wildly sensitive to smells) – but for the sheer comfort, I think we’re going to stick with it. We need to change out some of our sheets to deep pocket, cause with all the layers, it’s gotten quite thick. I may also want to add a thin wool mattress cover for some temperature relief as I wake up a bit warm in the morning. It’s actually fairly cold here in California now, and I don’t want to be roasting come summer.
Jim is pretty happy too – though he says when he sleeps late, he’s a bit achey when he gets out of bed – but that’s been true in a lot of beds, and he says that it doesn’t last – which is good. I’m not sure it’s a perfect bed, but for our price range + my back issues, I’m not sure anything would be. I’m pretty happy overall – which is a LOT more than I’ve been over the last few years – so I’ll take it! 
I’m happy to answer any questions that anyone might have if I can.
And Phoenix, as always, thanks for your patience on this forum!