Hi Sameeru,
Pros:
1) Only one or the number of clients configured by you will only contact Symantec endpoint protection manager for an update which then will distribute it to the other clients
2) Bandwidth utilization: You WAN bandwidth utlization would have reduced by a great number as there are only one or few clients trying to reach Symantec endpoint protection manager for an update.
If youe have 12.1.5 installed and running in your environment you will be using the ful benifit of GUP as SEPM will only be sending a delta provided SEPM has the same definiton set as the SEP cleint.
Cons:
This might not be excatly a con but i consider it as one. GUP monitoring cause it cant be done from Symantec endpoint protection manager you woul have to integrate another tool with Symantec endpoint protection manager for monitoring GUP
It is a brilliant tool to monitor GUP.
(SEP) Content Distribution Monitor / Group Update Provider (GUP) monitoring tool
http://www.symantec.com/docs/TECH156558
theres also a video for you to get a hang of the tool before you get started.
SEP Content Distribution Monitor - Introduction
https://www-secure.symantec.com/connect/videos/sep-content-distribution-monitor-introduction
From SEPM your options are limited, you can only generate a scheduled report for GUP update staus, refer to the article by .Brian
GUPs Schedule Report
https://www-secure.symantec.com/connect/articles/gups-schedule-report
Hope this helps, do post your question if your have any.