Got 6x470 (all sapphire Nitro 4GB, different mem chips though : 3 samsung, 2 elpida, 1 hynix) mining xmr @ ~ 4400 H/s. About 640W at the wall for the whole system so that's around 100W/card. No big difference between them in terms of hashing except for the hynix which is a bit lower (but it's the gpu on display).
Best choice regarding H/W and H/$ would be currently RX470 4G. However if you can find a 480 4GB at the same price, go for the 480
Those are some impresive results dude, only 640W for 4400H/s is just wow O.o
My server CPU's burn more wattage hehe.
The guys with mem tuning skills like Wolf0 or Eliovp will manage to get at the very least 10% more with the same wattage using their custom bioses.
As for me I only copied the mem straps (the 1750Mhz for samsung, the 1500 MHz for Elpida and Hynix), overclocked the mem, and slightly underclocked and undervolted core.
The big difference, when using Claymore comes with the -a 2 mode (I'm not sure about the numbers but it's something like -15% power usage with -3% hashrate).
I haven't played enough with Wolf0's miner and sgminer GM but i might try them this week-end when i have some time.