You've got a point there. I never actually used OS 9 on anything more recent than a 7300 until a couple of months ago. Then, late last year, I ran 9.2.2 on a 300MHz beige G3, and it was absolutely smoking.OS 9, for the simple fact that it ZOOMS on G3 and especially G4 Macs (I'm a proud user of Mac OS 9.2.1 on my 500 Mhz Quicksilver G4). No other version of the Mac OS I know of runs as fast as OS 9 does on any other Mac.
Except for startup time and Web-browsing, that is.