This haircut is great to customise to your needs and personal taste, it can be styled all back or slightly to the side, messy or more sculpted. It is of paramount importance that you get the proportions and balance right. Having some texture through the top will prevent the hair from being too heavy and too disconnected from the short sides and back. Like with most of these fashionable trendy haircuts, the disconnected fade requires regular upkeep, to keep it sharp and clean.
For the guys that enjoy their hair longer, the man bun is a great combination with the undercut. There is the options to wear the hair up or some guys enjoy wearing the hair in a ponytail. The most important thing to remember is to keep those sides tight and short.