Copying from WDTVLive to the rMBP is fine, very good in fact. Consistent, and a bit quicker than from the Win 7 laptop, which was around 3.5MB/sec.
WDTVLive is fed by an D-Link short N adapter, modem/router is a TP-Link W8960N. AP is set to bgn at 20Mhz. Channel is 1 I think, clearest of 1,6,11
Turned off Win 7 laptop so that what I tested was same setup as before except rMBP replaced the Win7 laptop. Other devices that are on and not in use are iPhone 4S and 5S, iPad Air and iPad Mini.
Thoughts? Was fine with Win 7 laptop, weird its same or better one way and a dog the other, the way I actually use.
rMBP is Oct 2013 issues, 2.3GHZ, 8GB, 512GB SSD