Z170 vs Z270, any differences other than PCIe lanes?

I'm assuming the Intel Edge Spring deal is going to have a 7700k so I am looking into upgrading and trying to keep the budget low. I'm thinking a used Z170 board but want to make sure I'm not missing out on anything the Z270 offers. The only difference I have been able to find is it has 4 extra PCIe lanes. I only plan on using a single video card and a single m.2 SSD.

Is there any reason not to save money and get a Z170?

The 200-series chipset is Optane Ready according to Intel, so if you think you may want to head down that path you may want to consider the Z270 vs. the Z170 and it's 100-series chipset. Otherwise, save money.