-- Last Updated: Feb-06-13 9:13 AM EST --
Unless you really want the look of carbon I would go with Kev-Lite. The boats are built almost exactly the same way. The difference is that in the graphite boat the outer Kevlar fabric layer is replaced with a lighter layer of carbon cloth. This accounts for the slight weight savings. That and the black trim are the biggest differences. Here is a link to the Prism spec page:
If anything the graphite boat is slightly less tough than the Kevlar boat, as Jackl's experience has shown. This is because the carbon fabric doesn't have any tensile strength to it and it is a little bit thinner than the Kevlar cloth so there is less material to abrade in use.
Thing with these boats is that all of their structure and stiffness comes from the PVC foam core. It doesn't really matter what materials are used as far as how the boat paddles because there is an absolute minimum of cloth in the boat. If it were a standard layup composed of layers of cloth the order and type of fabric would have an impact on strength or stiffness. But since it is a rigid foam core layup this doesn't really matter as much.
Here is how Wenonah describes the layups:
The graphite boats aren't really stiffer in this layup. Maybe theoretically, but not practically. You'll never know the difference.
Buy the Kev-Lite boat unless you really like the look of the carbon. If you like the look of the graphite and don't mind the extra cost, go for it.