The Slumberland Response Latex 4.0 Mattress is the top of the Response Latex range and the one I'd talk you out of. It has the same latex and the same 1250 support springs as the 1.0 and 2.0, then adds a plushtop and 3000 mini springs and stands 36cm tall, and none of those three would make me pay more. Skip it if you sleep on your front, and skip it if you were hoping to keep your current sheets.
Over four thousand springs, and 1250 of them hold you up
Slumberland counts 4250 springs in the 4.0's triple-layer system. Strip it down and there are 1250 full-height nested pocket springs doing the support, the same unit as the rest of the range, with 3000 mini pocket springs above them. Mini springs sit in the comfort layer and make it a touch livelier. Mostly they're a way to print a bigger number, and I stop counting springs well before four thousand.
Above the springs come comfort foam, a layer of latex infused with graphite and a deep quilted plushtop filled with TrueComfort fibres. The latex is the bit I'd pay for: bouncy, cooler than memory foam and long-lived. The graphite is meant to carry heat away, a small bonus I wouldn't buy the bed for.
The plushtop is the problem
I treat a plushtop as a pillow top. Pillow tops are the construction I'd steer almost anyone away from. The soft quilted layer is the first part of the mattress to flatten, it dulls the latex you paid for, and on a one-sided, no-turn mattress there's nowhere to go when it does. Rotating it every few months slows that down without stopping it.
Bensons sells it in Medium, Firm and Extra Firm, and that list makes the plushtop stranger still. A firm or extra firm spring unit under a soft quilted top is two different beds stacked on each other. The person who wants extra firm usually wants the surface firm too.
Heavier side sleepers only, and only in Firm
If you're a heavier side sleeper who likes a cushioned top over a firm base, and you'll rotate the mattress without being nagged, the 4.0 in Firm is a defensible choice. Read the sag clause in the guarantee before you buy. Guarantees measure a dip in centimetres, and a plushtop that has simply gone soft rarely reaches the number.
Front sleepers, walk on: the soft top lets your hips drop. Avoid it if you run hot and were sold on the graphite, because to my mind a thick fibre top holds more warmth than bare latex would. Avoid it if latex disagrees with you. And at 36cm, avoid it unless you're happy to buy extra-deep sheets and sit higher on the bed than you're used to.
What to buy instead
Buy the Response Latex 2.0 in Medium or Firm. It has the same latex, the same full-height springs and the reinforced edge, it sits 3cm lower and it has no plushtop. If you want firm and nothing else, the 1.0 gives you this latex build with nothing added on top. The 4.0 asks the most money in the range for the parts I'd least like to pay for.
