i still see that people are using AMD GPU's to mine but where as the obvious alternative will be to use Block Erupter kind of solutions to achieve higher hash rate ( i mean like crazy higher hash rate), so why is that people are still using GPU's rather than dedicated ASIC's? Any reason why?

Also I just bought Gigabyte 280x OC version for mining, u can consider the rest of the right to be a very good gaming machine, so using this GPU what kind of hash rate I can look at?
I tend to ask this question because I already have Win 8 , GTX 670 and I got 156Mh/s then this video shows as only 4.6Mh/s with 6 x 280x? is it a typo (I mean 4Gh/s)
http://www.youtube.com/watch?v=WfqfEpanpig
Also I am planning to install this OS
http://guiminer.net/bamt
Is it good?


Tks for you inputs
Happy mining.


P.S
If this is in the wrong section please move it to the correct one, tks and sorry!