They both have their place, one as a content discovery engine (Steemit) and one as a hub of discussion (chainBB).

I personally am not a fan on "nested discussion-threads" (where it puts each response directly below, creating a tree-like structure with branches), but I know many people are. Luckily, though the magic of the blockchain, we can all use the interface we prefer, share, talk and be a part of something much bigger!

To each their own :)