Quality wise, they share the same stats except a tiny difference in which the Whisper M 750W has (Multi-PCI-E - 6+2pin PCI-E x 6 more) while Formula Gold 750W has (Multi-PCI-E - 6+2pin PCI-E x 4 less) and both support multi-GPU.
Essentially you would go for the better deal ( Whisper M 750W) even with the tiniest details if pricing is the same.