Which PSU?

So Im running a Radeon HD 7850 and Intel i5 3470
Now my GPU says minimum 500W... but teh computer technicians informed me that 450W is more than enough, and they recommended this PSU

http://store.antec.com/Product/power_supply-basiq_power/vp450/0-761345-23540-2.aspx


Then there is also this one


Coler Master 550W  

Now I heard bad thinsg abotu CM's power supply?
Someone please reply fast :) 

 

DONT buy a coolermaster PSU, but DO get a 500 or more watt PSU. Antec is fine, but the best brands are, corsair, seasonic, OZC, XFX.

http://us.ncix.com/products/?sku=58382&vpn=CMPSU-750TXV2%20%2F%20CP-9020042-NA&manufacture=Corsair

http://us.ncix.com/products/?sku=57600&vpn=X-760%20Gold&manufacture=Seasonic%20Electronics

I got 2 of them that i would buy. First one is from Corsair the second one is from Seasonic.