Yup, the extra money you spend on a gold or platinum is quickly made back in the efficiency gain between psu's. I had a crappy bronze unit on my S3+, switched it to a gold and saw a 5% wattage reduction at the wall.
I try to get server platinum cheap
or evga 1300 g2
or if I get a deal evga 1600 p2
the evga cost but they have 10 warranty and I just use them in my next setup.
sometimes a server platinum can be found really cheap no warranty but if they are really cheap they are decent.
in a pinch :
corsair
seasonic
antec
have some good gear.
a bronze psu burning 1050 watts vs a plat burning 980 watts is 50 kwatts a month at 12 cents a kwatt that is 6 dollars a month. last winter I burned 5kwatts 24/7 that is about 30 a month for 6 months =
180 usd a year for 3 years of mning = 550 usd and all the psu's are under warranty except 1 server plat which still works.