Go test them out. I prefer Razer DeathAdder over Copperhead due to its high profile (higher back than other Razer mice).

Just wondering, is this the reason why your friend conclude that the DA is better than the CH?

Go to Lowyat, AllIt Hypermarket and try them out for yourself.
The DA, like previously mentioned, has a higher hump and easier to migrate if you're using a logitech.
The Copperhead is a great mouse, but alot of hardware problems MIGHT arise.
It's safer to just get either the DA, or if you like the contour of the Copperhead, try out the Diamondback 3G.
I switch between the Diamonback 3G and the Boomslang CE on my laptop and go home to a DA...... all EXCELLENT mouse.

And in other news Ever........
I'm sad to see the Firebird go, but the Mustang is a GREAT replacement for the new KITT!!!!!!