I have an IKEA mattress, the Sultan Erfjord. It is a latex mattress. We went through several mattress in the last few years, and all of them developed a dip in them. I decided on latex since that shouldn't happen with that. The mattress is on a platform bed, and is very heavy and very firm. Too firm for me, but we have a gel/memory foam cushion on it along with a pillow top for me. I have horrible knees and need more cushion than DH. I feel better about having a mattress that won't develop the dip and just replacing the top pads. It will be cheaper for us in the long run.
In the research I've done on mattresses, IKEA's seem to be you get what you pay for, some people love them and others say they're junk. Although in thinking about it, that's what's said about every mattress I've researched....
Debby