With the new Kaby Lake processor and its low power consumption can now fully utilize the potential of overclocking that will exceed the 5GHz barrier. Of course you also need to have the Z270 motherboard in order to unlock its full potential.
Although the new processor is still compatible with the 100 series motherboard, the new 200 series motherboards offer new map configuration for your system fans and improved thermal sensors boards like the ASUS offer fan controls that automatically react to CPU temperatures. It also fully support and improved the M.2 drives which now provide much more greater speed compare to 100-series. Four more PCI-E lanes where it allows more M.2 drives added to your system and benefiting for people who using multi-gpu.
The most notable changes are the Optane Technology, this is like a temporary cache in your system that will improved the file access in your files. Similar on Intel Smart Response Technology but this time it uses faster Optane drives that is connected via PCI-E instead of SATA port.
If you consider upgrading to M.2 based storage this Z270 motherboard is a good choice for you as the 4 more additional PCI-E lanes will benefit this purpose and with the Optane technology.