We chose cast iron tubs (Toto 1525's) when we reno'd our two main bathrooms. They aren't huge, or fancy, just soaking tubs, but IMHO cast iron is the way to go if your floor can support it (or will after adding add'l support) and the budget allows for it. Definitely solid, and supposed to retain heat better, too. We love ours. If we had had bigger bathrooms, it would have been nice to have a longer version (for stretching out while lying in the tub) but we were constrained by room size. Even so, ours are pretty roomy and very comfy and as I mentioned, solid.

Love my new Acrylic Kohler Archer tub! We did our bathroom about 6 months ago, so it's had plenty of use to really compare it to our Cast Iron upstairs. I love long tubs with a good book. First thing I love that was noticeable right away: With my cast iron, I need to fill the tub before getting in, other wise my back absolutely freezes when I lie down and my skin hits the cast iron. With acrylic, it doesn't feel cold to the touch, the way cast iron does. Also, the Kohler archer has a special drain that allows you to get a really deep soak with a higher drain, which I love! No regrets with the acrylic, and no issues at all keeping it clean, either. Even with use daily, sometime multiple times.

I will be installing an acrylic Hydro systems whirlpool (air's not enough for my muscles!) that is a delicious 19" deep, 42 wide and 73 long. After lying down in it at a local store, I found the slope of the back to be divine, and more suprisingly, the armrests to be vital with such a deep tub (I like to read in there). So it will clearly not even look like a cast iron tub. And I don't care!! Plus, a cast iron tub that size on a second story would cause me too much concern, particularly since the house was built with an acrylic whirlpool (pink-lovely). If the features that acrylic allows are important to you, don't be worried. The local store (Snyder Diamond) where I tried my tub (ordered on line) told me most people with very large upscale bathrooms such as ours are doing acrylic now, unless they want a traditional footed soaking tub look.

I just installed an acrylic tub and I'm thrilled with it - it's SO much nicer than the old porcelain monstrosity I had. The thing that everyone notices and comments on is the depth - it's much deeper than anything I could find in cast iron. I was willing to trade the duribility of cast for the depth. I think for resale, you'll probably find people on both sides of the fence, so get what pleases you and take good care of it - a tub in good shape will be a good thing, no matter what it's made of.