Well if you can get any other core for the same price get the other core. Dont get me wrong, clawhammer is still an A64 at heart its a good core and will perform basically the same as a venice at similar clockspeeds. The difference is in temps voltages, updated memory controller and of course overclockability.
I have two sledgehammer 1.6ghz optys and they run great, they have the sledgehammer core which is clawhammer for opterons, with no cool & quiet.