It appears that I am the first to review version 8 -- seems very strange (??). But in the few months that I've used it, I am torn between updating or staying with MX 2004. Many of the bugs in the 2004 version have been addressed -- as well listed here :

http://www.versiontracker.com/php/feedback/article.php?story=20040727005522950

-- and overall version 8 seems far more stable (I rarely ever crash it, whereas with 2004 it would crash constantly, and I was always hitting SAVE in a fit of [warranted] paranoia). I can scroll with the mouse, use the shortcut for copying and pasting frames (VERY nice), zoom in and out and scroll with the hand tool more easily/smoothly (and without crashing), etc.

BUT (and this is a huge but) . . .

The program overall, and in general, runs so ridiculously slow that I feel like I'm working on a Mac Performa (if you remember those). I'm running a G5 dual 1.8GHz with 3.5GB of RAM, and I can't describe how tedious it is to wait for Flash 8 to respond to each little thing I attempt to do -- very, very frustrating.

And, unfortunately -- even though both 2004 and version 8 use the same version of Action Scrip (version 2) -- you cannot open Flash 8 files in Flash MX 2004. So, you kind of have to decide whether to make the leap or not, and then do it (or don't). I should say, though, that you can open MX files in Flash 8, and then save them as 2004-compatible files; problem is, every time you save them in Flash 8 (unless you "Save As . . ." and specify otherwise), they are Flash 8 files and not backwards-compatible.

Last remark -- related to MX 2004. In my experience, DO NOT update from 7.0, unless you want to wait several minutes for your files to preview/publish. In 7.0 it's quick, but after the updates (7.1 and/or 7.2), I've found that every time you want a Publish Preview, you wait an eternity . . . (Maybe I'm just too impatient.)