The difference between our 9", 10" and 12" Botanical Bliss models varies, depending on the firmness you choose. Each mattress has its own unique attributes. Whatever your body type or sleep preferences are, we can help you find the bed that will help you sleep better than ever before. SOFT / MEDIUM: The taller the mattress, the more soft talalay latex is used in the top comfort layer. Our 9 inch model is topped with a 2 inch comfort layer; our 10 inch option with a 3 inch comfort layer, and the 12 inch model with a luxurious 5 inch comfort layer (a 2 inch over a 3 inch comfort layer). In our Soft and Medium models, the thicker talalay on the 10 and 12 inch models gives these mattresses a softer, plush feel, preferable if you're a side sleeper or prefer a softer mattress. The 9 inch model, on the other hand, is ideal for side sleepers who need a little more support without sacrificing comfort. MEDIUM FIRM / EXTRA FIRM: In our Medium Firm and Extra Firm models, all three thicknesses have a similar feel since firmer latex is used in the comfort layer on all three models. Instead of sleep style, body weight becomes the deciding factor when choosing a firm mattress, since the amount of firm latex needed in the comfort layer will depend on the amount of weight pressing against it. We recommend using the following guide in selecting your medium-firm or extra-firm models: 9 inch model Ideal for those who weigh up to 225 lbs 10 inch model Ideal for those who weigh up to 275 lbs 12 inch model Ideal for those who weigh up to or over 275 lbs When you combine the hypo-allergenic, temperature regulating, and eco-friendly characteristics of latex foam with the unmatchable comfort and buoyant support of our carefully engineered Botanical Bliss line, it becomes obvious that any of our 3 models (9", 10" or 12") would be a wonderful addition to your bedroom. Remember, our 100-night comfort exchange policy allows you to find the Botanical Bliss comfort that's just right for you, even after it has been delivered.