Just like the name says it, a mattress foundation, or a base, is simply a platform for your mattress to sit on. Regardless of what type of foundation you choose, it should provide even and adequate support for the mattress. While the base itself will not affect the comfort of the bed as much as the mattress itself, the type and quality of the base will have at least some effect. Therefore, the first priority for a base should be its ability to support the mattress evenly. Then come the comfort and other additional features.