Ben is wearing a medium length hairstyle that has short layering all over. The front hair is styled to stand out and the rest of the layers are styled forward. This is a very trend hairstyle. Most of the time Ben can be seen with the classic medium length mens hairstyle, see below for details.
This type of medium length style will require frequent trims to keep the layering in place. As you hair grows out, so do the layers and the end result is a very bulky mess. Most men can go 4-6 weeks between trims. If your hair grows fast, you may need a trim in 3 weeks.
This style, see photo left, features slightly longer layers in the crown area with the sides and back kept shorter. Overall this is a very attractive medium mens hairstyle.