I'm pretty neurotic when it comes to the type of bathtub that I want to have in our home someday. I grew up in a house that had a porcelain-on-steel bathtub. It was super easy to clean and maintain and the non-slip pads that you put at the bottom of the bathtub worked perfectly for this type of bathtub material. It was easy to clean the bathtub and get it white again by pouring in water to almost the top of the bathtub, pouring in some clorox and letting it sit for an hour, then draining the bathtub and perfecto - you have a very white and sparkling clean (bacteria-free) bathtub. Since moving to California and touring a lot of new and older homes around the area, I've noticed a new kind of bathtub becoming popular: acrylic. This is the same material that we have in our apartment. It just SUCKS BIG TIME. I HATE acrylic bathtubs - they are so difficult to clean and maintain. Dirt sticks very easily to them and you have to scrub your ass off to get them sparkling white clean. I can't even put those cute pads on the bottom of the tub that help with the non-slip factor. It's not even worth it to pour in clorox and clean it the way I used to clean the bathtubs in Wisconsin because it just doesn't work with this acrylic junk.
I understand that whirlpool tubs are the 'in' thing these days and obviously, acrylic is used for such tubs because it's inexpensive and quite a bit lighter than porcelain-on-steel. However, I've definitely resigned to the fact that I will gladly forego a whirlpool tub so that I can have a tub that cleans easily, is durable, and lasts a very long time (not to mention a tub where I will be able to place those cool non-stick things).
I've been doing some research on bathtubs and fell in love with cast-iron bathtubs. It's the most durable bathtub material and naturally, like with everything else in life, I tend to fall in love with things that are at the top of the price range. I also still hold porcelain-on-steel bathtubs close to my heart because I find those very long-lasting and very easy to clean (from personal experience).
I've found a cast-iron tub that I really like: http://www.us.kohler.com/onlinecatalog/detail.jsp?from=thumb&frm=&module=Baths&item=467002&prod_num=868§ion=2&category=10. I love Kohler products (and not just because they are located in Wisconsin). Here are some of Kohler's other cast iron bathtubs.
If you want to learn more about the different types of bathtub material available, check out these websites:
1. Keidel