In all fairness, I should add that in areas where the water is hard or high in iron content, it could conceivably stain the stone where it's tough to get the stain out whereas with porcelain, you can use harsher chemicals if need be.

Yeah... water quality is a big part of the equation, IMO.

My current house has very high iron water. If the softener isn't on [or is out of salt], turns stuff orange in a matter of days, can ruin a white shirt in a single trip through the wash. I'd never be brave enough to do natural stone here, no matter the sealer.

But the water at the new house is much better, and I'm very, very tempted...

I'm considering marble, too. Is there a way to test your water for iron content? It would be a big disappointment to have the marble turn orange. I stayed in a hotel recently that had a beautiful marble 12x12 shower. Most of the tiles looked fine, but in a few areas, I saw the orange and wondered what could cause it.

I too am in the same position. I'd never thought of having a marble shower - that is until vacation. The shower was beautiful and we both fell in love with "the look." Our neighbor just did their master shower in marble - very nice looking. Of course our design will kick their design!!! But I can hardly wait for this to begin. We're going for marble. Decision is made.

Talk to someone in your town office. They should be able to direct you to a local lab that tests water.