There are now internet lists of compatibility problems with software.

As above, I would recommend waiting a week or two before installing it so that the 3rd party vendors have time to eliminate the compatibility problems.

I have a friend who is using snow leopard and is also having compatibility problems with her programs which worked fine with the older OS.

Upgrade went just fine except the compatibility problem with WideMail

I can't comment on any new features, but it works as it's supposed to.

10.5.8 was still there and everything worked as if nothing had ever happened

I bought this program from the apple store to install on my 20'' iMac, previously running os x 10.4, & after installing it and updating everything, it worked as if brand new