Both processors should be fine but if you look at value in long term, I believe 3600 is definitely a step in the right direction.
Given both 6700K and 3600 are identical in IPC (correct me if I'm wrong), with 6700K (4C8T), if you were to run into core-limited issues in the future, you'll probably have to ditch your setup (best supported processor on H110 is 7700K) and spend additional amount for another processor/motherboard bundle. You most likely won't need to worry with a 3600 (with 6C12T), and even if you feel like upgrading, you can swap a 3700X or 3900X(?) and call it a day.