Top of the line Blizzard card is 380Mhz+ with very high speed memory access. High speed memory access alone changes the way blizzard card performs even at a low 270Mhz. Bvision performance has also increased due to modification where the PCI bus is clocked from min 37.5Mhz to 41.5Mhz.
I'd love one, but I wouldn't make use of it to justify the cost even the cheapest cards go for. Which I think is probably where this thread is going. If you will use it then bid, if you won't then nobody expects you to.