A clean installation took about 13 minutes from start to finish, which is a world of difference from the hour or so that a clean 10.5 Leopard install takes. Other then the time involved, there are very few differences between the 10.5 and 10.6 installation processes at this time.
Once you're up and running, it feels very similar to Leopard. I don't know how much this will change through Snow Leopard's development, but don't expect a terribly different interface. The subtle changes to the current Aqua definitely look good though.
The biggest changes are under the hood. Snow Leopard is fast. Very fast. Like, surprisingly fast. From boot times to general application usage, Snow Leopard was noticeably quicker then Leopard when using the same system. Apple and 3rd party applications alike, they all launched faster and performed smoother. I'm sure this can be attributed to the new 64-bit architecture, but its amazing how much of a difference it really is.
Now on to the software changes. Right off the bat, there were new (unreleased) versions of many of Apple's "staple" softwares. Quicktime, Bootcamp, Mail, even the Address Book have seen updates. Address Book's most notable feature is the Exchange Server integration so happily boasted by Apple at WWDC.
Don't want to hotlink all the images so click the about this mac to go to the rest.
