What are the pros/cons of Oracle's Grid Control compared to DB Control?
In Oracle Grid Control you can make a global view of your entire enterprise. 
This is an advantage above DB Control.
It is slightly easier to authorize employees for certain targets in Grid Control.
If your mail gateway changes, you have the advantage of only one location to change.
When making clones, Grid Control has the advantage of not having repository parts in the target databases.

On the other hand, 
DB Control is closer to the database and most of the times better support for new features.
Oracle Grid Control Requires quite some resources to run and in many cases at least one dedicated dba to keep it running.
You have no single point of failure for management.
Oracle DB Control is very easy to setup.
With a little smart thinking you can build a central page with links to all DB Consoles that you want, complete with links to the documentation.
Grid Control easily gets mixed up when making clones, even without a local repository in the target.

I think it is a personal choice. At the moment, after having wrestled with many GC installations, I think having an own repository for historic data and links to Oracle DB Consoles is not a bad idea.