Fireworks CS4 has quite a lot new features, compared to Fireworks 8!
(( I hear that Fw CS4 may be a bit unstable on MacOS 10.6 Snow Leopard, but I also hear most of the issues are now resolved. Anyway, you may not have a problem, so if Fireworks CS4 works fine on your Mac, then don't worry! ))
Fireworks has Pages + Master Pages, Layers (+ sublayers), and States, of course. Fw 8 had only Layers and States.
Fw CS4 has a new text engine (Adobe Type Engine, ATE) which has quite a new nice features (but one is missing: you cannot anymore make right-to-left text orientation in it! so you must know this before moving to CS4!)
There are also Smart Guides implemented, which may help you in your daily design work.
CS4 also better supports PSD files (open and save) and AI files (open).
9-slice scaling tool -- this is new to CS4 and helps me quite a lot, too.
Sure there are other improvements, too, but these are the ones I can think of, at first glance... Anyone else, to add something to my short list?
Hope this helps you!
Many thanks for the reply, FW CS4 is on it's way and I cannot wait.
Regards and God Bless
Glad that I helped you!
Please, if you experience any problems with your copy of Fireworks CS4 on MacOS, report the problems here, and we'll try to help you as soon as we can! :-)
-- here you can also read about some possible incompatibilities between Fw CS4 and latest Snow Leopard!
But it might as well be that everything will be smooth as silk on your side, so no worries in advance!
I myself am using Fw CS4 on Windows XP Professional for more than a year now and have no troubles!
Also, be sure to update your copy of Fireworks, right after you install it -- there's an important patch that can be downloaded from:
...or via Adobe Auto Update.
Hope all of this helps and I wish you happy designing with Fireworks CS4!