As Roger noted, the Kona is no match for the Serenity in subplanning. In fact the Kona is no match for ANY dedicated board in the conditions these boards are made for. Comparing the Kona to the Serenity in subplanning is like comparing the Kona to an Evo in waves. The Kona however does both.
The strength of the Kona is its scope, both for sailing conditions and rider's level. If you can afford a quiver and always have the right board at the right time with you – don’t buy a Kona.
Any chance that the Serenity will come as a two parts assembly?