Its not necessarily corsair, its their cheaper units (CX and VS specifically) the HX and AX units are generally praised highly, as they are made by Seasonic or Felxtronics. The former are made by Channel Well who uses cheap capacitors that cause short life spans. While they last they are good, just from a longevity standpoint units made by Antec, XFX, and Seasonic are almost always preferable.
My buddy thought he was safe buying an HX 750 but it needed to be RMA'd...then the replacement was broken too...so Corsair (realizing their unit is crap) gave him an AX 760i.
The HX 750 is made by Channel Well, the AX lines are made by Seasonic or Flextronics entirely. the HX and TX lines are a mix of Seasonic and Channel well. The only Corsair i could ever recommend would be an AX unit. On the other hand i would feel safe recommending ANY XFX unit because they are ALL made by Seasonic. Most Antecs are made by Seasonic or Delta thought their cheaper units are Channel Well.