Acrylic, cast iron, or Quarrycast (lava limestone) tubs?

We're remodeling our bathroom, and are replacing an oversized cultured marble garden tub that we rarely used. I'm considering an air bath versus a regular free-standing tub. I thought my choices were primariy between acrylic versus cast iron, but then came upon a Victoria Albert Volcanic limestone tub (Quarrycast... Englishcast) in one showroom and am wondering about how well they hold up (25 yr warranty).

Anyone want to share opinions of cast iron versus acrylic, versus resin, versus Victoria ALbert's Quarrycast?

tub

Sit in them before you buy it. Some will probably be just as uncomfortable as your "garden tub" was. And just as cold.