[0] Appearance [1] They can be in any color but typically all look similar since they are almost always one story buildings. They can be single, double or triple wide. [3] The appearance can be customized to the home owners preference. Traditional homes can accommodate any architectural preference. [2] 
Appearance can be the same as any traditional site-built home. You can add any style of window, door, wall or architectural feature you prefer. Once completed you can not tell the difference between modular and traditional homes.