Just like real stone and other natural resources, there will be certain variations between colors and textures with each piece. This is more so the case with tiles that have a through-body composition. These tiles are not topped with a special glaze layer, so there will be more variations in coloring. Because of this, you may want to pick through to make sure each tile complements the others.
Glazed tile is more uniform in color and texture, but there can still be some variations. Your color options are much more extensive with glazed tile, so your options for specialized design can be tailored more to your personal style.
In rooms such as the bathroom, you will want to make sure that the tile you put in has a low rate of moisture absorption as well as slip resistance. Moisture absorption is directly related to the density of the tile. The denser it is, the less moisture it will be able to absorb. For this reason, high-grade porcelain is much better than ceramic, since porcelain tile is far denser.
Slip resistance can easily be applied to tiles when you order them, while some come with it already in place. As a rule, the shinier the tile, the more slippery it will be. So a highly glazed tile is not a good choice for the bathroom unless area rugs are used.