This one is tough! I get asked this almost everyday and there is no way to tell what is the best. We are all so unique in shape, size and mentally. Don't believe anyone who tells you whats best. It's all on you!
First up is you.
How do you sleep? I once got told by a customer who was having a lot of difficulty sleeping that he needed to lie in a particular way to test the mattress "I need to lie on my back and have my chin touching my chest with my hands by my side with palms facing down."
First thing I asked was is that how you sleep? I mean maybe it was. It wouldn't be the strangest position I've come across. It wasn't though.
A sale person had told him that was how he needed to try their mattress. This gentleman sleeps on his side.
Immediately this changes everything. He went from liking a medium firm to one of our softest.
Again I can't stress this enough that you are unique and you are the only one who feels exactly what you feel. But as a general guide if you are a back/tummy sleeper you require something slightly firmer to support the lower back while a side sleeper requires a little more pressure relief and contouring to allow for the shoulders and hips.
Before you go into the store think about what it is you want out of your mattress. Do you have trouble with a sore shoulder or does your partner wake you up 2 hours early every morning because he/she starts work early.
Next up is feel.
Some people love firm some soft and of course some people love something in between.
Feel is to me the most important thing. The main thing we need to do is actually get to sleep. If your lying in a bed that's firm thinking I cant sleep but I bet my back wont be sore tomorrow then your not on the right mattress.
One think to bear in mind is technology has changed sleeping on a firm mattress doesn't mean your better supported.
Traditionally firm meant support and soft meant pressure relief. Now we have technology that means we can do both at the same time. 9 out of 10 times if you lie down the same way you sleep and the mattress feels right it is.
Lastly Is the support.
Now support is the hard one to put a finger on. But one of the biggest things here is that the mattress will age and soften.
The comfort foams and the support underneath it whether a coil of some description or a foam support will wear in. This is where quality really starts to have an impact. Quality foams and coils make a world of difference and you will start to notice this just 6 months in. The industry standard today is a 10 year warranty across the board most retailers and manufactures will put the 10 years some when the mattress really doesn't deserve it. Even Australian brands have been forced to compromise quality to attempt to keep competitive.
We personally also need to compromise on durability sometimes. Your needs may prevent you from getting the strong durable bed. Pocket coils for example are fundamentally weaker but they provide such a unique combination of contouring support and almost eliminate partner disturbance. Alternate to that firm support units offer great durability but can be a little less contouring and depending on the exact spring design can go from a moderate amount of disturbance to quite a lot.
So in summary no one knows what the best mattress for you is. Like shoes there is no style or size that suits everyone.
But to give yourself the best chance avoid anything that doesn't use Australian made foams, Lie on a few find a salesman you trust and who listens to your needs.