Consult for to change servers CentOS to Debian GNU/Linux

[Javier Enrique Tiá Marín <javier@eftssc.co.cu>]

Hi everybody:

In University of Oriente, Santiago de Cuba, we want to change the most Servers 
to Debian GNU/Linux, but:
- All Sysadmins used Clones RedHat (CentOS)
- All Servers are DELL and DELL don't SUPPORT Debian GNU/Linux
- For long time testimony and real test the use the RedHat + Sendmail is  
strong, for example:
a RedHat 7.3 + Sendmail outdate for 2 years vs 1 GBytes messages without 
failure:

Based in your experienced, another testimony and knowlegde:
You believe in the change?
Why?
Howto?

do you given any directions for to continue research?

At end We don't find anything concrete could simulate various mayors 
situations showed above.
The Sysadmin a Sysadmin the numbers tell the last word.

I'm all ear.

TIA,
Javier

p.d: Apologize but my poor english