The screen alone is worth the upgrade. Not having to swap wireless card and microdrive is a nice bonus. Not running out of memory is a super nice bonus. The PIM appplications are fine for me, far better then they were on my first Z, although not much changed from the 5600.
Some minor bugs in the 5600 are fixed. The bug where it take forever for the Z to come out out screen saver mode if left on overnite isnt fixed. The most annoying difference I\'ve found is that the 6000\'s appletviewer wont fetch web pages and run the applets in them, it only works on local pages. Opera has problems rendering some pages that rendered fine on the 5600.