Been using it for a few weeks now and seems similar to X11 in many regards. Doesn't seem to like older Type 1 fonts though, but not sure if it's a system level issue. Illustrator doesn't seem to like displaying fonts in the text palette either... Not sure why.
Quark 7 seems to behave fine with it and I haven't used type in Photoshop, so can't offer any feedback on that particular application.
If you're using X11, I'd suggest saving your money and keeping it for as long as it's usable. The additional features with Fusion don't seem overly miraculous.
Macbook: 2.16Core2Duo,4GbRAM,DL Superdrive, 120Gb HD
The Old Workhorse:G4 1.4Ghz,1.5Gb RAM,Radeon 8500,Airport,Sonnet ATA133 Card, USB 2.0, 250 Gig HD,LG & Pioneer DVD-R