The number of major mattress makers is about to shrink again. Four years after Serta and Simmons combined under joint ownership, Tempur-Pedic has now gotten approval from the Federal Trade Commission to acquire competitor Sealy. The resulting pairs of brands will together command more than 60 percent of the market, according to Reuters.

But as we report in our first comprehensive mattress tests in Consumer Reports' history, buying from a major brand is no guarantee you'll get the comfort and support you need to feel refreshed in the morning. Our Ratings of six innerspring and six memory-foam mattresses assess mattresses from Tempur-Pedic, Sealy, and other brands for back and side support, claimed firmness, bounciness, durability, and other criteria.

The resulting combination of the latest merger shouldn't further complicate mattress shopping, though that's cold comfort since model names for a single mattress are often different from one retailer to another. Our advice? Use our performance Ratings as a guide, along with our buying advice. And insist on the precise makes and models that scored well in our tests.