I don't think you would be able to buy something of that spec for as little as that as that is a pretty good deal, but I still think building your own is better in any situation so if you can stretch your budget a little then I would go for it.
Like some have already said its a good deal, very nice system for the price.
Only issue I have with it is I couln't find the PSU specs, looks like its not even listed. So you dont even know the wattage/amps let alone brand and model. Im sure with some digging you could find out. If you do any reading on these forums you know how important the PSU is.