This is a very tricky question to answer. There is no one-size-fits-all type of firmness. I challenge any mattress company that claims they have the perfect mattress for all. It’s very much a personal preference and is very difficult to chose for every person and sleep characteristics. A firm mattress to one person is not firm enough for the next. Same goes for plush. It’s been my experience in over 10 years in the industry that half the population prefers plush and the other half a firm mattress.
What exactly is firmness in a mattress anyway? Firmness is basically the feel you get when you first lie on the mattress. If you feel that you’re sinking into the mattress, it’s probably on the plush side of the scale and if you feel that you're floating on top it’s probably on the firmer side.
Another thing to consider is how you sleep. Side sleepers tend to prefer a plush fee where a stomach or back sleeper prefers a firm feel. Again, this is very subjective and rules don’t apply to all.
The firmness question by far is the most difficult one to answer especially buying in a brick and mortar store. Typically you’re lying on the mattress that you think you’ll enjoy for the next several years for only a few minutes at most before your choice.
A Bill’s Bed offers the best of both worlds. A firm feels on one side of the mattress and a plush feels on the other. Try it at home for a 100 nights (or 50 per side) at no risk. If it’s not right for you, I’ll give you your money back and donate the mattress to those in need.