Usage – bbPress is a just forum software while BuddyPress is a social networking plugin. If you just want to receive comments, set topics and let readers discuss them, then bbPress is a really good choice. However, if you want somewhere people not only can create new topics or even new forums, but also can integrate into groups and exchange messages between themselves. Then, BuddyPress is your choice, which has advanced communication system between groups of users.
Feature – It has a self-developing system which can automatically gather people into a group according to their communities or organizations. Besides, as BuddyPress has a longer history than bbPress, thus, it is equipped with more advanced and useful features such as group discussion forums.
Plugins – It has more applicable plugins reaching 533 while that of bbPress is 162. Thus, the former one is more easy-to-use.
Management – As we have mentioned before, BuddyPress can help you build a big forum and setup many discussing groups. However, this practice comes with hard working and time consuming on management of these groups. On the other side, bbPress comes with simpler function and accordingly, it is much easier to manage.
Thus, if you want to develop a big website with a large number of fixed readers, better go with BuddyPress. However, if you want to develop a small-to-medium sized website, bbPress is a good choice for the easy management.