UUID performance as primary key

Hi Guys,

I am interested in finding out the pros/cons of using UUID as a primary key field. My requirement states that UUID
wouldbe perfect in my case as I will be having many small databases which will link up to a global database using the
UUID.Hence, the need for a unique key across all databases. It would be extremely helpful if someone could help me
figurethis out, as it is critical for my project. 

Thanks in advance,

Nav