Colours. There are unlimited colours to pick from too with bathroom basins so take your time to find one you really like. There is no right or wrong choice so find something that works well for the look you wish to portray in your bathroom. This is a change that can be part of a huge remodel or it can be the only part of that room you plan to change.
Today thanks to advanced plumbing and modern technology the bathroom may well have evolved as far as it can. With luxury steam rooms and hydrotherapy baths it's difficult to imagine how bathrooms could get any more sophisticated. That said the bathroom like any room in the house is ever changing in terms of design trends.
Pay Attention to Size. If you plan to use the same insert location where it already is you will need to shop for bathroom basins that fit that same size. You will also need to get one that is the same shape. Some are square or oval while most of them are round. If you want to completely change it up you can go with a different size and shape.