The Masonboro buoy is closer to Wrightsville and will give a better indication of size on the beach, the FPS buoy is farther out in deeper water but will give a good sense of the size of the swell as it approaches.  You can click the 'tacks' above to go to the graphs or view details.  These can come in handy after dark when you might not be able to see the size as well at the beach or on the live cameras.