I checked out consumer reports before buying from OMF. They get good ratings. So, we purchased both our kids' twin beds from there as well as our guest bed queen bed. Pretty sure we bought the cheapest or close to it. They are just fine. We then purchased the most expensive king bed that they sell for us. Within 2 weeks, there were indentations. Not kidding. So, we flipped it. Same thing. Flipped it again, as instructed, for a couple months. Same thing. It's AWFUL. I was nursing a newborn, and it was awful because the slant was so much. She also kept rolling onto me because of the slant. Of course, this made me very worried for safety reasons.
I looked at the fine print in the "lifetime warranty" that comes with all their mattresses. It says that the indentations are "normal & natural." And, they only give you a new mattress if the indentation is 1.5 inches or greater. It doesn't sound like a lot, but it is. I've measured, and ours is at about .75 inches when you're not lying down. It's hard to measure when you are lying in it, but it's definitely a lot more.
Of course, I told the sales guy that we were replacing our 10-yr-old mattress because of indentations. Never did he say anything about the "natural or normal" indentations in their mattresses. There's more of an indentation in OMF after a few weeks than our other mattress had in 10 years.
We're still sleeping on it, after over 2 years. I keep thinking I want to buy the $800 memory foam one from Costco. I've heard good things about it.
I guess my advice would be to not purchase the ultra pillow top one. I can't remember the name. But, maybe one of the middle-fluff ones would be good? My dad & his wife have that kind & love it.
Happy sleeping!