Waterbed mattresses vary from Extra Firm to full motion. Select the style of waterbed mattress you want from above and then you can look at an individual waterbed mattress by rating of the specific features you are looking for. 

Selecting the best waterbed mattress for you is important. You will be sleeping on it for many years.

Some experts advise getting waterbed mattress with a similar waveless rating to what you have been sleeping on if you were happy with your current waterbed mattress. Generally a firm waterbed mattress are listed as Waveless. If these are too firm, the semi waveless waterbed mattresses may be what you are looking for.