UPDATE 2012-08-30: I am not sure if the module is now fully compliant to the new ISO 2007, but bug reports are certainly being responded and resolved now. Updating rating from 1-star to 4-star. Thanks, Kim.
2012-02-17: Review to version 1.47:
Sorry to have to rate with 1 star. I don't have problem with the interface/documentation. The 1-star rating is just to warn people that the data used by this module is not up to date. And that months-old bugs are not being fixed.
At the time of this writing, this module still uses ISO 3166-2:1998 (first edition) when it should be updated to ISO 3166-2:2007 (second edition) + all the newsletters (minor updates). For example, this module does not report 3 newer provinces in Indonesia.
Sadly we live in a world where countries and subcountries change all the time.
EDIT: Ok, so I was not being clear that I was not talking about my own bug report (posted at about the same time of this review). And bugs were certainly being resolved up to about 7 months ago.
An invaluable module that I have used for years. As a previous reviewer suggested, it can be more useful to populate a data store than loaded in a running application, though 2MB isn't really much these days.
The only reason I cannot yet rate it 5 stars is the module does not yet supply UTF-8 encoded data. Hopefully the patch in RT#38559 can be applied soon.