There's also a good ROI on platinum/titanium psu. Imagine gold psu = 89% efficient, titanium = 94%.
The psu is 1500W, and you use 1200W. 5% efficiency difference is ~ 60W lost.
60W over a year = 60*24*365/1000 = 525KWH wasted due to poor efficiency.
If your electricity rate is $0.10, thats $52 lost. Over 5 years, that's $250 due to efficiency loss. If you're in mining for the long haul, it makes sense to go for platinum/titanium psu
Most Gold rated power supplies do noticeably better than 89% efficiency across most of their rated power range - EVGA and Seasonic in particular usually just MISS "Platinum" rating on their G2 and X series power supplies.
Also, long term you aren't likely to be profitable at 10 cents / kwh - the last few months have been a noteable exception but NOT the norm - since most of the BIG farms are paying less than 5 and commonly closer to 3.