Here are the observations I made of how it is better/worse in comparison to GeekLog..
- Topics and sections are seperate entities, just like on the major weblogs
- So easy to install, absolutely anyone could do it; the config file only has options relating to the database, and everything else is done invisibly to the user by the system
- Pretty much everything is configurable through the web interface; no need to edit text files
- Tons of cool modules, built-in and available with no additional downloading necessary
- Plenty of very nice themes pre-installed, and many more available to download
- Makes it easy to add RDF feeds..I was able to easily add feeds from my favorite geeky websites to my front page in under a minute, without having to look up their RDF URL.
- Advertisement, forum, private message, and journal modules built-in, along with countless others
- Actually has comment and story rating systems, even if they are broken and not configurable by the admin
- That 'modules' block is just plain annoying, and the fact that its present on so many phpnuke sites reduces the respectability of yours
- Comment rating system only worked with a select few versions of IE..it didn't work with older versions of IE and every other browser I tried
- Downright awful security..my regular user account was allowed to rate comments as many times as I wanted, the story rating system's feature to prevent repeat voting didn't always work.
- Confusing admin system separates admin accounts from non-admin accounts.
However, having the knowledge to fix the problems listed above as I do, the decision becomes much harder and I might just pick phpnuke due to its feature-packedness and the sheer number of extra goodies available.
For my own site, I've already chosen GeekLog for my site while ago, and will stand by that choice.