Corsair is generally a really good brand. However, their only bad psu is the Corsair CX line-up. They use crappy channel well capacitors so they are low-quality, which is why it's much cheaper than others.
Yes, 750w is overkill. But look at the price. $55 for 750w? That's extremely cheap for a good quality psu. The 550w version is $55 as well.
I think going $2 above budget is worth the extra quality you're getting.