That's not a good advice. First of all, even the worst platforms today don't consume more than 100W (most are at ~50 W idle consumption). No idea where you're getting the "130W" figure from. But that's just nitpicking, not really important. What is important though is that GTX 970 has 145W TDP. So 4 of those can easily draw 600W from the PSU. Of course one can (and should) undervolt the cards, but PSUs are always selected based on at least the stock TDP (cause cards crash sometimes and revert to the stock settings by themselves). And then, how are you going to connect a mining rig with 4 gtx 970s to a single 750W PSU? Most of 970s have 2x pci-e power connectors each. So, to power a rig like this you'll need at least four molex/6-pin connectors for the risers, and then eight(!) pci-e connectors for the cards. Have you ever seen a 750W PSU with so many connectors? I haven't. There are some 970 cards with single pci-e power connector each (Strix and EVGA Mini-ITX come to mind), but it's still too much of a stretch in terms of total power anyway.

A decent 1000W PSU will work fine. The good brands are Corsair, EVGA, Seasonic, CoolerMaster, BeQuiet. Look for popular Gold/Platinum units.