Whether your preference is to sleep organic, like the green Avocado mattresses, use a cooling mattress to help keep the summer heat at bay, or you’re a side, back, or stomach sleeper, the most important factor to look for when selecting the right mattress brand: one that keeps your spine aligned while applying supportive pressure evenly to your body (kind of like a hug). Ultimately, the best mattresses should allow us to sleep happily and soundly. The rest — like size, price, and material preference — is pretty variable. Each of the R29 testers ahead used their own unique set of parameters to evaluate the individual mattress they tested — everything including foam models, hybrid innerspring and padded, and even sustainably made mattresses.