If it were me, I would install ceramic or porcelain tile, and instead using regular sanded grout, have Laticrete non-sanded grout put down. It doesn't discolor OR mildew. For our guest bathroom, I designed the layout for it and the installer suggested using Laticrete instead of regular grout, and I agreed. It costs more than regular grout, but WELL worth it! I absolutely LOVE it! It looks as good now as the day it was installed. If anyone wants to see a picture of it, send me a PM with your email address. Just yesterday I spoke with the installer about removing the grout in our master bathroom and installing Laticrete, so he's working on an estimate for me.