I've done this a few times in the past with mixed results. Some things to keep in mind is that all the modules that your portal uses need to be on the destination install before you apply the template, or else it will just skip over that content. Another problem I had was that the linkclick and fileclick URLs were all broken after the import, I wrote a few SQL query's to clean those up if your interested. Any reference to a page or a file that includes the old portal id in the link will be broke, I also have some SQL that will fix this for you. Users will not get moved, but there are other modules that can help with this. Any module that doesen't support Iportable will not have it's content moved over. There might be more that I'm missing. Your best bet is to just give it a shot in a staging environment, and see what works and what doesn't. I hope this helps, let me know if you have any other questions.

Thanks,

-Nathan