Slipper baths

[Nepotism]

I'm having my bathroom done next month and keep hearing conflicting stories. Should I be going for plastic, cast iron or what? I prefer the look of cast iron and would like to be able to paint the outside, but I've heard they cool down quickly.

They do cool and they are heavy but I find the flexing in my acrylic slipper bath a bit off putting. It also cools quite quickly although not as quickly as the cast iron one in the main bathroom.