Thank you very much Michael, you touched exactly on my problem - exactly what I was talking about!

Yes, I agree that the surfaces are actually joined but perhaps a coined term is they're not aligned?

What I typically do as in exactly the vertices you circled is to move them around and merge them together, add additional edges where required etc., but obviously it becomes very time consuming when you try to dense up the model at export to make the matching a bit better...

I noticed that selecting quads/tris DO seem to help get better alignment between the edges of varying topologies but then you end up with more work.

I definitely understand how complex this issue is but I've always held the opinion is that the value in MOI is FIRST its mesher and second, its GUI!

If you can conquer this delima then I'll definitely expect to see you stealing awards from ILM, Pixar and others along with all kinds of magazine and blog articles! ;-)

-Will