So I have an investment coming up and I'm not sure which would be best, should I buy 4 USB antminers running at 1.6 GH/s each or should I take the money and buy a fraction of a bitcoin with it so I can invest it into the cex.io mining pool?

I already have a cex account but having the freedom to switch pools with the antminers seems attractive but they won't be as fast as the amount of GH/s I can get at cex.

Any advice would be greatly appreciated, thanks in advance.