Bitmaps are great for your basic raw or edited photo. They're as close as replication is going to get to the real life imagery. They also have an atmospherical grain that can make foe a nice contrast between the hard edge and graphic style of vectors and other design elements. Bitmaps are directly proportioned to their original file size and pixel dimension so if you distort or make a scale change you have to make sure that you do not stretch the dimensions beyond their limits. If you do it will cause for large out of focus/grainy images.
Vectors are not based on the width of a pixel, but on shape alone. Because of this you can stretch a vector image out as large as you want. The danger here is for there to be some issues with proportions after an image is stretched so far. Vectors do have a clean line that defines their edges, and can work together with themselves or be used to spice up a bitmap image. They can translate well within many different formats which makes for quick editing.