IMO, it's just another on of those "fanless" products that needs a fan close by or at least some serious airflow...
I'll take that any day over a video card with a 40mm or 60mm fan a non standard fan header and a heat sink so small that even a 120mm fan won't cool it quietly.
I'll also take it over a fanless HS that isn't flat and leaves you with no easy way to add a fan to it.
Seriously. I'm currently using a Radeon 5570
with a 120mm fan on 5v blowing across it (hanging at an odd angle by wires tied to the CPU HS and the back of the case). A card with a HS that big and flat would allow me to strap a 120mm fan flat to it instead of having to rig something unstable like what I did for the 5570 I'm using.
And that's assuming I don't just go into RBE and slow the darn 6850 down enough to leave it truly fanless. Give me that 6850 and the monster HS and so long as it's faster than a 5750 after I take RBE to it I'll be willing to let it run fanless at less than stock speeds.