This quad-core with eight threads is a high-end processor that will bring a few small changes. It will be faster within the same TDP, but Intel is not talking about the actual clocks. The fastest Skylake is the Intel Core i7-6700K and it has a 4.0GHz base clock that reaches 4.2GHz on Turbo.
Kaby Lake Core i7 7x00K series will be slightly faster. Intel is telling its partners that the Kaby Lake-S will have 15 percent more high speed input / output lanes. This is only four additional PCI express lanes and nothing that is going to change the world.
Intel Rapid Storage 15 is unique to Kaby Lake-S and the Intel Optane storage technology support. Intel has made us update motherboards to support PCI-e drives and it will do the same with Intel Optane, storage technology that will rely on PCI Express Gen 3.
Intel supplies DDR4-2400 memory support and it plans to teach its graphics a few new tricks. The desktop CPUs are expected in Q4 2016 which is quite late to the game, but better late than never.
The upgrade market will buy it as long as it arrives before Thanksgiving and Christmas.