I sail Nacras, the reason is simple. They are freakin fast. Its the hull design, they are efficient, and they lack the problems of other catamarans. Hobie's for instance seem to all have the "banana" shaped hulls, i had a hobie for my first boat, this hull shape is hard to tack, and it tends to make the boat pitch-pole easily, plus htey just aren't in the same league as far as speed. Most nacras also have boomless sails, whitch is a plus. Bottom line is speed though i think, Nacras are also more stable, but if hobies were faster i might overlook that. fortunately, they aren't.