One thing I noticed the other week and have only just had a chance to invesitgate further is that Fireworks doesn't have a Label or a Text component. There is a good reason for this; it doesn't need them. If I draw a rectangle path on the stage and export it the rectangle is defined as an Image and a gif is exported with the MXML file to fill that position. But try placing a piece of text onto the stage and then exporting to MXML. Fireworks will define the Text within MXML as a Label. It will also define a Label style to define the appearance of the Label. Even more interesting if you add a second seperate piece of Text with some difference in appearance it will define two custom styles to define the appearance of the two Labels and add the styleName attribute to the Label. There is one final piece of intelligence that ensures the Fireworks to Flex workflow is spot on. Add a multi-line piece of Text to the stage and export. What you'll notice is that the multi-line text is exported as a Text component and that a Text style is defined.
This capability to appropriately export Text into mxml isn't mentioned in any documentation I can find and isn't immediately obvious when you look at the Flex Components. But it certainly is very useful once you know about it.