The differences between DB8, DB6, and DB4 are as follows:
DB8 uses an ambidextrous lever that can be swapped to either side of the bar. The DB8 lever also has full MMX clamp compatibility. DB6 uses a non-ambidextrous lever that is left/right specific but still integrates MMX compatibility. DB4 uses non-ambidextrous levers that are left/right specific and does not have MMX integration. The power and on-trail feel of DB8, DB6, and DB4 is the same. With DB6 and DB4, we were able to bring the performance and consistency of DB8 down to lower price points.