I have both and would only buy MSI again due to ease of programability, noise, max output and heat.

* 6 MSI RX470 X 4gb GPU RIG
* 1120 H/s (186 ave h/s per gpu)
* 880W at the wall
* 1.27 H/W (Hash per Watt)
* Settings = 1500 strap, 1900 mem, 1300 core.

Although, If you can get good pricing, I would go for the MSI 480 4gb.  The MSI 480 8gb is usually out of the price range to be efficient for the output you will get.