I haven’t used Discourse – though I must say that it looks really interesting. I have, however, integrated CBOX with CiviCRM on a number of sites and have written a number of plugins to facilitate this – you’ll find them on the WordPress plugin directory if you want to try them out.
It’s probably easier for me to respond in detail to more specific questions, but my main observation is that it can be a great combination if you have the resources to keep on top of the maintenance that’s required. You’re looking at a lot of moving parts and keeping them working well with one another is not a trivial task.
Cheers, Christian