I worked at a mattress store and I can confirm that the most important factor is your individual compatibility with a certain mattress. Not a mattress manufacturer, not huge price, but mattress must suit you as much as possible. That's why I always advise to test a mattress in a real store, you need to check a level of firmness and quality of support by yourself. Memory foam is rightly considered the best on the market, but it is really pricy. On the other hand, official warranty on memory foam products is very long, these mattresses are really durable and can serve for ages. If you don't want to spend much money, you can always buy a memory foam topper, here's a nice review on the latest models by the way https://sleepissimple.com/best-memory-foam-mattress-toppers-reviews/ .