2 recommendations

Absolutely do not buy a mattress without laying on it for awhile. Go shopping and bring a book.

When checking reviews, don't consider folks opinions on comfort, they're not you. Do look at reviews about durability.

When I met my wife, she had a water bed. I didn't care for it but she loved it. We moved it to my place and used it for a couple years before deciding to replace it. Looking back, I think the biggest problem was it was simply overfilled

Some friends have a Sleep Number and have mixed opinions. They find it comfortable enough but state that the divider gets in the way of extracurricular activities.