You can browse the categories at https://forum.sublimetext.com/categories.
In general, Discourse does a better job of keeping the spam at bay, and providing features (like syntax highlighting) that users find helpful. Unfortunately there are some downsides too, but it does seem overall to be an upgrade from PHPBB.
There obviously are some things that would be nice to change, like a simpler UI and less of a reliance on lazy loading and other JS stuff that lags slower machines. Unfortunately there are only so many hours in a day.