The main reason was the fact that we were (still) on version 10.2.0.3 and we experienced some troubles with that version. Also Oracle anounced the problem with this version regarding the end-of-life of the SSL-certificate on Dec 31th 2010.
The installation went very smoothly. See also my other posts about this subject.
The only problem we encountered with this new version was that the 'Performance Graphs' froze after a database restart of one of the monitored databases.
It is expected that there is no response anymore for the graph to build up, after a database shutdown, but you would expect that the graph just shows nothing, but keeps advancing in time.
This was not the case.
Also after the target database was restarted, the graph still kept showing the status before the shutdown. Nothing could be done to get over this, except a complete restart of Grid Control.
After such a complete restart, the graph refreshed and started showing real-time information again.
We started a Service Request at Oracle Support for this and thanks to DITO ( Demo It To Oracle) we were able to clearly show to Oracle support what happened. With CamStudio I recorded a complete movie about the problem and send it to Oracle Support.
They immediately recognized the problem as being bug 10307099 and supplied a patch for it.
This solved the problem.
I was very happy to see the power of CamStudio to help me in clearly showing/explaining the problem to Oracle Support. This encouraged me to use it in other cases as well. And it is free !!!