Antec is a reliable brand however i am not sure how good their PUS are in the 700-800 range. Most of the Antec power supplies i have seen people do their builds are usually around 400 to 600 range.
Please make sure you have the right connections or enough connections in whatever power supply you buy. Unless you plan to O/C + 2X graphics cards I don't consider 800 watts a good buy. Then again who knows what your build will have