The Prindle 19mx is certainly a competitive and well respected boat with a great racing history. As far as rating goes, check http://www.ussailing.org/portsmouth/tables02/tables02mh.asp for the Portsmouth ratings between catamarans (the lower number is faster). The Prindle 19MX is rated slightly faster than the Nacra 5.8 (which is also 19'). I am not sure if the Prindle 19mx rating includes a spinnaker but I know the 5.8 rating does not. The P19mx is almost identically rated with the Hobie 20 and so on....