i've been a phpnuke user since february of this year, and for awhile there, i was pretty involved in the community, and i stuck with it, since i had not found anything better
phpnuke has a HUGE community, but the problem is, there are so many splits in the community... the lead developer (Francisco Burzi) has a tendency to screw over the community (the details of which i'm not going to go into, it's a long history..), and until more recently, there was no 'dev team', it was just the one official developer that didn't support phpnuke, put out a buggy product filled with security holes, etc etc
the reason why phpnuke has such a big community though, is because of how *easy* it is to modify or hack the code... which also causes problems, since then many of the addons that you find, totally alter the core nuke code, which means that every release you want to upgrade to will overwrite any changes that have been made, and your 'addons' no longer work
nukecops.com has fast risen as the 'support' site for the community, and they became so big, nukecops.com started to dwarf phpnuke.org, at which point Francisco allowed nukecops.com (the staff/developers) to become the official dev team (but their code submissions are still implemented at a slow rate by FB, for some unknown reason)
it's a troubled community, tons of people argue about GPL, licensing, argue and fight about Francisco Burzi, some support NukeCops.com, others support NukeScripts.net, etc etc..
i've gotten tired of the bs, the bugs, the security issues, so all new sites that i release will be built using Xoops2. the XOOPS CMS is the easiest that i've ever used, the most bug-free CMS i've ever seen, and from what i can tell, is very secure... it has a great community and very helpful developers that are actually committed to the product
there are rarely GPL arguments from what i've seen, everything is much nicer here.
I will be moving my existing phpnuke sites to Xoops, once a few modules that i need are converted to Xoops
btw, these are my nuke sites:
http://www.csmapcentral.com http://www.nukebbmods.net <<
and i have a XOOPS site in development:
http://webhostingparadise.com << (site is currently shut down to anyone that's not me, lol, while i work on it)
i hope i helped you some. btw, if you absolutely must go the *nuke way, i would suggest watching
http://www.nsnnuke.org << it's a branch from PHP-Nuke with many code rewrites and security fixes, it's still in beta phase, but i'll bet $$ that it'll be bigger and better than php-nuke, and it might even give XOOPS a run for it's money...
nsnnuke isn't ready for production sites yet, but XOOPS is, so i'm sticking with XOOPS