I've set up a test farm to see how the SSRS 2012 performs with SharePoint 2010. The advantage of using the 2012 version instead of the 2008 is that the reporting services will be available through a service applcation. The insights on how to setup this service application will follow in the upcoming weeks
My testfarm has been configured so it has the 3-tiers on a seperate server so we can simulate scenarios where a person could experience some double hop issues.
During my testing I got an error message stating that "permissions granted to user are insufficient for performing this operation "
I checked my sharepoint logs and nothing in particulary popped up so i started troubleshooting the issue. In the end I found a post on MSDN that helped me out (link).
What it means is that the user is added twice to the user list. Removing one of them (in my case the one with the standard notation DOMAIN\User) resolved the issue.