[krismusic]

is there a reason why bass from a BA would have a different quality to a dynamic driver?

 

[jarrett]

There is a reason why BAs have less bass (in a single driver design), but that's a good question as to whether the quality of bass sounds different.

 

[Spyro]

is there a reason why bass from a BA would have a different quality to a dynamic driver?

No, none.  It is still a preference issue.
 
I always thought dynamic bass had a lazier, more relaxed nature to it until I heard the IE800 which was amazing.
 
5-8 years ago I may have given the nod exclusively to dynamics but now with multiple BA driver set-ups being the norm and advanced crossover networks, I think the BA's lack nothing from the dynamics.  Futhermore, it seems there is more flexibility with "molding" the sound of a BA driver whether it be a slow or warm or dark presentation to a super tight, quick or bright articulation. 
 
I think at this point they are on even ground SQ-wise.  For anyone that would insist that dynamics sound more "natural" I ask you to try the Westone Pro 50.