The disadvantages of using SWFAddress is that the communication is slow and it had to change the uri, which is not always something the developer needs. In general the the Flex application listens for uri changes, simply by setting a timeout for a listener with very short period of time, like 10 milliseconds, and if some change occurs get’s the uri, parses it and process the changes.
From the beginning the hard-coded listening of the uri change is not a good idea. Even for very short timeouts it become risky when the user can click and skip an important refresh inside the flex application.
There are tricky parts, of course, but in general it’s a secure and reliable way to talk between these two technologies.
A sample of the process you can find here.