Ask HN: Whiteboards - porcelain or melamine?
Is porcelain worth the difference in price?
OTOH, if you're just going to write and erase as is most typical, melamine is nice because when somebody inevitably comes and writes in permanent marker on the board, you don't feel bad throwing it away for a new one.
However, like the parent said, if you have a use case that requires magnets, porcelain is the way to go.