What kind of baby bathtub is best for a newborn?

Across the reviewers we read, newborns do best in a tub with a soft mesh sling or contoured support that holds their head above the waterline, such as a 3- or 4-stage convertible tub or a dedicated newborn bath support. Parenting-community threads repeatedly stress that the sling or support is what makes the difference in the first few months.