I have been an avid WordPress user for just over 2.5 years. During this time I have tried and tested about 6 stats solutions. I have tried Google, the Statpress(s) and Cystats, played with Wassup and even got Piwik up and running. All excellent statistics collectors - some easier to use and learn than others. I have switched between them on several occasions and in the end... I always seem to come back to WordPress.com stats.
(Note that for performance reasons I choose to run only one stats agent at a time)
Whenever there's been a genuine issue/bug with the software - I have found the author(s) responsive and diligent whilst finding a solution. All software is going to have issues from time to time - some are quickly fixed whilst other take a little longer.
I have on several occasions had issues with this plugin where the cause of the problem lay elsewhere (eg: profile/cache issues with WordPress.com and flash issues in browser).
Currently (2.6.5 + Hybrid + 20 odd plugins) the plugin is working as good as and has been for the last few versions.
I strongly suspect that several of the "not working" topics going up on this forum lately are due to issues not related directly to this plugin.
Finally, I would like to take this opportunity (in light of the recent CMS Awards) to acknowledge the self-less effort by plugin authors in making WordPress an even better product. Thanks.
Papua New Guinea