Some Pros and Cons beyond CPU that I thought of:
1. Only the Z170 would have PCIe 3.0 x 4 for M.2 SSD (Most Z97 have only PCIe 2.0 x 2 for the M key M.2 SSD and budget Skylake i7 Pre-builts like
this one don't have any M.2 slots for
PCIe NVMe SSD....only SATA M.2 SSD. )
2.
Only the Z170 would be able to use RAM speeds over 2400 (the Z97 would be limited to DDR3 2400 and the Skylake i7 budget Pre-built DDR4 2133)
EDIT: Z97 Can also use memory speeds over 2400 (Eg, DDR3 2600 to DDR3 2800). Sorry for some reason I was thinking about AMD's limitation when I wrote this.