I have porcelain in my foyer because I actually thought it looked better than the marble. It of course is more durable also. Here are some photo's. Paid $3.29 sq. ft. for it from a local tile store. It is their brand, not a national brand.

This is also rectified porcelain:

Looks beautiful....and slippery!

These floors look beautiful! Are they slippery? Has it ever been a problem?
I was all set on getting polished porcelain and my contractor just told me its very slippery if I put it by the entrance and the stairs to second floor. I have little kids....what am I to do?

Thank you!!!

If you are going to install marble or a derivative thereof, you might consider covering it with an area rug to avoid scratching the floor especially if the product is not as resilient as actual marble. Just a thought :)