One caveat about IKEA mattresses: being a multi-national company, verify the mattresses and linens you're buying complies to the same sizing in your region of the world; they can differ and there's always stories about how IKEA sheets don't fit standard sizes or fit them well, at least.
I've bought mattresses from Ikea in the UK, China and USA.
In all three of those countries, Ikea sells mattresses in the regular local sizes. I recall that, maybe 20 years ago, Ikea in the UK only sold beds and mattresses in their native (Swedish? Euro?) sizes. But, in the last few years, I've bought both beds and mattresses from Ikea that are standard UK and standard US sizes.
Of course, it's always good to double check the actual measurements of your old/new mattress before pulling the trigger.
