When looking at the PCB design, it becomes clear that MSI has gone long ways to improve the AMD reference design for extra overclocking potential. The included SSC coils work without emitting any coil noise, and the added number of PWM phases will help in situations that require large amounts of power fed to the GPU. But it seems to me that during normal use and during overclocking with the stock cooler, these features seem to make little difference.
Out of the box, the card comes with a fairly small overclock which only adds about 2-3% to the card's performance compared to the reference card. I am also puzzled why MSI did not increase the memory clock - there certainly seems to be enough headroom to do so.
One very serious issue in my opinion is the excessive fan noise coming from the card. In idle the fan is running much faster than required, resulting in a high level of background noise. On top of that the card will immediately change fan speed when the temperature changes the least bit, which makes the fan much more noticable. For normal desktop use this makes the card unusable unless you manually adjust the fan settings to something more decent which can easily be done using MSI's included Afterburner utility.
Afterburner which is made by my good friend Unwinder, who also makes Rivatuner, is clearly one of the most advanced and easy to use software for GPU overclocking. It comes with loads of features including voltage control, fan control and on-screen display during games. Even though the voltage regulator can go up to 1.85V, MSI limits the voltage adjustments to up to 1.35V on this card which seems reasonable for the included air cooler. As mentioned on the overclocking page, the Twin Frozr II cooler on my card suffered from bad contact, but that shouldn't be any problem once you strap your own dry ice or LN2 pot to this baby to get serious with overclocking, as has been demonstrated by Hipro on XtremeSystems forums the cards can reach almost 1500 MHz with such cooling methods which is really impressive.
Now the big question: is the card for you? If you will be using the card out of the box or do some mild overclocking, I think there are better alternatives with less fan noise and better pricing - for example the PowerColor HD 5870 PCS+. Should you however plan to break some records, then this is the HD 5870 to get. Its design clearly begs for sub-zero temperatures and the price difference to all other cards is reasonable enough to make this a no-brainer.