About Eve Mattress Eve Sleep are a mattress retailer that proudly boast ‘the world’s most comfortable mattress’. Humans, by their very natural are cynical when it comes to claims like this, but over the course of time that Eve Sleep have operated they have set out to achieve one goal, and that is to produce and sell exactly that. Now they feel that they have achieved that goal and cannot wait to share the end result with the world; and for the cynics, they are offering a 100 Day home trial completely free with a guaranteed free return if you’re not completely satisfied. Don’t believe them? Try it for yourself!