A lot goes into what makes a mattress work for someone. I always look at the bedding when we visit hotels since they put a lot of thought into what will work for large numbers of guests and be durable. I think weight, sleeping habits, and body shape are probably the most important factors. The whole idea is that the body is not contorted, but supported in all the right areas. That's going to vary a lot between people, but most fit into the medium-firm category.
Personally I'm a side sleeper around 195 lbs with a bit more lordosis than average. I hate mattresses that are too firm because they force my hips up causing a pressure point and aggravation of my piriformis. Softer works for me- but not without decent lumbar support. Otherwise my back flexes and that causes pain. We bought a medium soft Kluft years ago and that was great, but recently replaced it with a soft Winkbed. So far it's been two nights and the jury is still out. My sleep app says I'm making less noise. The bed definitely feels hotter than the Kluft, which I don't like. It might be the supplied Wink mattress protector though. We can return it in 30 days if it doesn't work out. A few of the hotels we stayed at and liked the bedding used various incarnations of the Beautyrest.
For pillows I've always been a fan of the Pacific Coast luxury pillow. I see they don't sell that exact model anymore, but it was expensive and 100% down. Every now and then they would have a huge sale and I'd buy a bunch.
