The various features of a wakeboard determine how is performs. Most manufacturers of wakeboards print information to help you to choose the correct board for you. Often however the description is very limited, with some of the advice to follow you can make a more informed decision.
Most beginners for example will prefer a wakeboard with squared edges. The reason for this is that it allows for more control and stability for someone who is not ready for the bigger air tricks (which would be better with a rounder board). Thus more advanced wake boarders would be better suited to rounded edges on their wakeboards in order to perform tricks. These result in less of a chance of catching the edge in the water when landing and are more aerodynamic allowing for greater speed and easier lift off.
Boards also come in single and twin tipped varieties. While a single tipped board is pointed at just one end and squared at the other (usually the back) a twin tipped board is rounded at both end.