@onlinebit & @kisaragi - thanks for the advice 
@onlinebit - you mention you're going back to 270X's on your next rig; better hash rate in your experience or is it a cost/power issue? EDIT - I found an answer at the link below, might go 270X's instead!
http://www.overclock.net/t/1454426/r9-270-underrated-the-holy-grail-of-mining-rigs-2-important-metrics
It seems 5970/7950 models are nigh on impossible to get for under $330 (second hand...) in my country but the 280X (toxic) model is ~ $420so I might grab one of those to begin with.
Thanks again!
@onlinebit - you mention you're going back to 270X's on your next rig; better hash rate in your experience or is it a cost/power issue? EDIT - I found an answer at the link below, might go 270X's instead!
http://www.overclock.net/t/1454426/r9-270-underrated-the-holy-grail-of-mining-rigs-2-important-metrics
It seems 5970/7950 models are nigh on impossible to get for under $330 (second hand...) in my country but the 280X (toxic) model is ~ $420
Thanks again!