Ranked in these QuestionsQuestion Ranking
Pro Open source
Source code is available on GitHub under GNU General Licence.
Is built to be extensible and flexible.
Pro Premium extensions
There are many great developers creating premium extensions to make it go to the next level. With those premium extensions phpBB goes far beyond any other.
Pro Huge extension repository
Its the forum software with the most ready to go extension repository.
Con Outdated look and feel
Even the latest version of the software looks like the typical '90s forums which is now pretty outdated.
Con Slow (phpBB 3.0)
phpBB 3.0 was not optimized for slow connections.
Con Poor community communication
There is a release lifecycle, but it is not adhered to. Migrations and updates cannot be planned.