There are a few other, relatively minor differences. The fan for example, mostly though the only one that doesn't follow spec exactly is the Hercules, which uses (I know it's slower, but don't quote the numbers) 4 ns DDR-RAM as opposed to the 3.8 everyone else uses - now I haven't seen overclock comparisons but I naturally think that faster RAM would let you bring it farther past spec, but on the other hand - Hercules is known for being a good card.
Overall they're the same, heck - put on your own cooling for the RAM and/or GPU and you have one as different as the rest.
Stolid