LOL! The IIfx or the IIx? ;D
The 700/900 are the beginning of the next period, interesting as well, but hardly unique.
Dunno, I don't think the point is to run the most powerful Mac overall, it's to have a period piece. The initial post asks about the fastest of the II series and that would be the IIfx with all its foibles. They make it a very interesting Mac indeed. While 8MB may not seem like much now, it's twice the standard IIfx config. This from an era of very expensive memory when its IIci stablemate was shipping with a mere 1MB allotment. Wicked fast was half the story, when it shipped the IIfx was the fastest Micro on the planet and for most purposes, upgrades outside of a more capable Video Card to run a TPD as a second monitor in 24bit weren't required for even high end applications such as CAD or DTP.
The 700/900 are the beginning of the next period, interesting as well, but hardly unique.