Flash MX is Flash 6.0 by another name. The MX moniker might be a little bewildering at first, since it isn't technically the version number. Rather, "MX" is being added to the title of Macromedia's new Flash, Dreamweaver, Fireworks, and Coldfusion releases as a branding exercise. A related strategy was employed several years ago when the company prefixed the word "Shockwave" to their Flash, Director, and Authorware players. Flash Player 6 is the accompanying player version for Flash MX.
Flash MX has so many new features that it's a challenge listing them all. Some are minor, some are major, some useful, and some not so much. It's fashionable to categorize new Flash features as either "designer" or "developer," but to me that's a false distinction. Instead, I've listed them all together in semi-random order.
Mac OS X Support
Flash MX is the first Carbonized version of Flash, allowing it to run on Mac OS X and take advantage of the Aqua interface. The app doesn't feel as snappy as it does on Windows or Mac OS 9, and unfortunately it's still prone to locking up the system. Most annoying of all is that the user interface (toolbar, panels, etc.) hides itself fairly regularly, forcing manual reactivation. Hopefully the disappearing panels bug is something to do with the OS itself, to be fixed in a future update. Keep your fingers crossed.
Macromedia refines its standard user interface from year to year. Flash MX looks similar to Flash 5, with a few major differences. It has inherited the Properties inspector from Dreamweaver, as well as a new system of dockable, collapsing panels. Instead of the old Adobe-like tabbed panels that could be organized into horizontal groups, this new setup features panels that can be joined vertically and then popped open or shut.
Without dual monitors, it's likely that you'll find yourself grappling with overlapping windows, panels and inspectors. The Panel Sets feature and keyboard shortcuts do help, you just need to get yourself into the habit of using them. Creating your own panel set is easy enough; lay out the workspace to your liking and then choose "Save Panel layout..." from the Window menu.
Even with their new look, the substance of most of the Panels hasn't changed a great deal. Artwork creation is almost exactly the same, with the notable exception of a free distortion tool, used to manipulate raw graphics.
The new Timeline acts a lot more like it did back in Flash 4, and includes a few new features. Frames and frame spans are easier to move around because the hand cursor has been switched back to the regular pointer. Layer Folders have been added, making it easy to group layers together and collapse them. This folder feature really makes a difference when designing complex movies, reducing a lot of timeline scrolling.