Corsair, like most vendors build several lines of PSUs to fit various market niches
AX/HX is there top end, designed for the most discerning PC enthusiasts who are looking for the best possible overclocks. Most of these are great tho the 1000 and 1050 watt models are dogs.
TX series is the next one down, designed for those who do not want a "budget" PSU but don't quite want to invest the cashola in an HX or AX series. Stick with the V2 version and avoid those with M suffix.
CX is Corsair's "Builder" line, designed to be attractive to mass market system builders builders where price is among the top priorities.