In terms of productivity, the Ryzen 1700 will have a bit of an edge over the i7-7700k with Blender. If you could step up to the 1700x, which is close to the price of the i7, you'd get a marked improvement over the i7 with Blender. As for gaming, in most games right now the i7 would take the lead. The higher clock rate (among other reasons) matters more than the higher core count of the Ryzen 7. It's not that the Ryzen is bad at gaming, its just (depending on the game) not as good as the i7. It's kind of the standard when looking building a workstation, good high core count productivity but lower single threaded performance on things like games.
As for the original question, the extra 200 might be worth throwing towards a Ryzen 1800x...