No.
Personally I can't see how one board can outperform another that uses
the same chipsets, the same CPU, the same drive interface and the same
memory.
The only comparison I can think of is the GFX card market. The best
NVidia cards, for example, only outperform the others by a few FPS and
thats usually because of higher specced ram.
Perhaps someone can explain?
Anyway I'll be happy buying a G4@800Mhz from a company I've dealt with
for years. If I do need Firewire at some point I'll buy a PCI card.