Multiple NSs or multiple glue records

[Gustavo Lozano]

I think that sometime ago I read a post about what is better multiple 
NS or multiple A for the same NS. Some of my colleagues and I are 
having a discussion of what are the pros and cons of the following 
cases and maybe someone in this list can contribute to our discussion.

Case 1.
example.com.   IN        NS       a.example.com.
example.com.   IN        NS       b.example.com.
example.com.   IN        NS       c.example.com.
a.example.com IN        A         10.1.1.1
b.example.com IN        A         10.2.1.1
c.example.com IN        A         10.3.1.1

Case 2.
example.com.   IN        NS       a.example.com.
a.example.com IN        A         10.1.1.1
a.example.com IN        A         10.2.1.1
a.example.com IN        A         10.3.1.1

Thank you.


Gustavo Lozano