[again] New Mining rig (which gfx)

Hey guys, I know it's kinda bothersome, every day couple of people want tips and hints about building a new rig. But nevertheless, here it goes

I read alot about mining and put together a beginner rig (and ordered most of it), consisting of:

1 x Z170 Gaming Pro Carbon
1 x be-quiet-dark-power-pro-11-1200w
1 x 4 GB Ram
1 x G3900 CPU
1x inter-tech-ipc-4u-4129-n

The raisers i still have to order.

The big question however is ofc which gfx to use. Energy prices here are around 0,3€/kWh so from what I read I "should" go with Nvidia GTX1070 cards... But I did some calculations and the RX570 seem to be the better deal, since I can buy double the amount of cards. I wanted to start with 2x GTX1070 but for that money I can buy 4x RX570 (if I find some).

So what is your opinion, which card should I go with. I try to call some local stores tomorrow and see if I can get my hands on some RX570's for ~220€ each.
Would 560's be an option? I read they do around 15MH/s and consume half the power of the 570's. So I could buy 7x 560 sintead of 4x 570
Or do you guys think I should go for the GTX1070?