Funnily enough, we've had two cups fail on us in the Cali this year spilling hot liquid everywhere.
One was a porcelain type (? not an expert) with a picture of a split screen (which became a split cup). It was really cold at the time so it was still freezing when we took it out of the cupboard when we poured the hot water into it (the cup, not the cupboard ...).
The other was a melamine one which just split from top to bottom on me last Saturday . Maybe it's my driving
So an enamel one would be more durable, but don't the contents go cold quickly?