In general, a porcelain tile is harder than a ceramic one and offers greater design flexibility. Although both are made from clay and other natural occurring materials fired in a kiln, the clay used to make a porcelain tile is more refined and purified. It is also fired at a higher temperature and greater pressure, resulting in an extremely dense and hard material.
Porcelain tiles are an ideal product for cold weather climates where freeze/thaw conditions are a concern. Due to its low moisture absorption rate, porcelain is less likely to crack and is more impervious to stains.
Certain factors however do make using porcelain tiles a more difficult DIY project. For example, their density and hardness require the use of a wet saw with a porcelain diamond blade as they are harder to drill & cut.