Worth it sometimes.
I really like the simpllicity and ease of use for the factory recommended CDI flexible furler on my 26X. Works everytime with no maintenance, and is easy to transport without disassembly.The gennaker term just means an asymmetrical spinnaker. The asymm is flown just like a genoa for the same angles you would use a genoa. The weight and shape are quite different as they are intended for different amounts of wind. There is a significant advantage to the gennaker or asymm in light air. The deep wide belly of the sail made of very light weight cloth usually about 3/4 oz. fabric, fills and stays filled more easily and pulls the boat along as if there were 5 or more knots of air than actually exist. When you wing and wing in light air, the weight of the sail cloth in the main and jib or genoa, usually 2 to 3 oz. fabric, causes sagging which destroys the best airfoil shape, ot it's not as efficient.In good air, say 10-15 knots, then the light weight assymm is reaching it's maximum range of strength but really makes the boat fly because the light weight also allows a bigger sail area from the same rigging... in the Mac for example the genoa is about 200 sq.ft. where the asymm spin or "multi purpose sail" is about 350 sq. ft. In addition, with the downhaul on the asymm you can use it as a genoa for reaching or as a dead down wind spinnaker by letting the tack fly out in front of the boat.Bottom line is this: if you have frequent light air, or is you cruise downwind for long distances in medium air, you will use it and enjoy it. If you are on a body of water that has constant winds of 15 or greater, you probably won't.