I use the Saatva graphite cooling memory foam topper on top of a tempur pedic and its amazing. Pricey, but in my mind, worth every penny--I feel like i'm floating. More on reddit.com

There are two types of tempurpedic toppers. There is the original supreme and then there is the adapt + cooling. If you purchase directly from tempurpedic the toppers are not returnable. Many reviews (and my own experience) show that typically these toppers can be 1" to 2.5" short. I believe they'll let you return/exchange if it's 2"+ short. The adapt is extremely plush in a warm room. The type of plush where your whole body will slowly sink in and make it difficult to roll around. It's currently out of stock and after discount and taxes a king is ~$380. The ONLY cooling feature is built into the cover. It's small pockets of cooling gel. The reason the cover does not work to cool you is that in order to release the heat you have to roll to a new "cool" spot. Since you sink in so much to the topper you will hardly roll through the night. Also, since you sink more into the this softer material it traps more body heat than the firmer topper. The original supreme topper is made of the original Tempurpedic material. It's going to have a much firmer feel and you'll sink into the mattress slower (as it capture your body heat it will soften). I'd probably shoot for this model and purchase off of Amazon. It's about $30-50 more than directly from Tempurpedic, but it will allow you to return the topper (if you can fit it back into the box) for free if you don't like it. There is no cooling feature. It will more than likely sleep hotter than the latex, but perhaps not as hot as their adapt model of topper. More on reddit.com

Don’t do it! Tempura-Pedic used to have a great product I would have sung their praises to anyone. Their toppers used to be made of 5.7lb density foam. Over the years they reduced to 3.5 (2018 ish). You’ll see a rash of reviews from that time with people complaining. And then again in summer 2021 they reduced to 2.7lb foam which is basically useless. They won't admit to it or even tell you their density because it's “proprietary” but I was ticked enough I tracked down old products on eBay that were still new in the box and had the people selling them weigh them for me. That’s how we figured out the years of the changes and the actual densities. Our old topper was 50lbs without the box. Our new topper we just ordered was barely 30lbs IN the box. And they don't accept returns. 😤 Got a 5lb density from this place and am very pleased with it. https://www.foambymail.com/product/5lb-memory-foam-topper.html More on reddit.com

It feeling different doesn't mean it's inferior. The industry has been moving more and more towards "faster response" memory foams on the basis of consumer demand for the last few years. Tempur has been a hold out on that. But faster response foam, while it might not be your preferred feeling isn't inherently inferior. What would make it more objectively inferior is if the overall weight is lower. Do you happen to have the package weight for each one? Or have some way of weighing each? EDIT - it's on the law tag. The new one is heavier, so I think odds are low it's an inferior product. EDIT EDIT - I see u/regaphysics comment now and I realize I didn't notice they're not the same size. So I did the math. The queen size one (I guess the new one) has a density of 2.3lbs, while the twin size one (I guess the old one) has a density of 3.5lbs. So actually yes, you are correct -- it is an inferior product! More on reddit.com