Well documented, efficient implementation.
The free database you can get from maxmind is already pretty good;
if you happen to need the more accurate database you can buy it and
just replace the free database; no need to change the code.
Thanks for this wonderful module. It would be really great if you could do dependency checks on the underlying C libraries to make sure it does not break in the installation process. At least a big printed warning/message would be helpful and save a lot of peoples time :)