I should make one point clearer: I will not give up the Sourceforge account, but I must move the repository because Sourceforge does not provide Bazaar. It's important to mention that cloning and updating the repository with Bazaar is as easy as with SVN.
I'm thinking about moving the bug tracker to Launchpad; some pro's and contra's: 1. Launchpad is importing the Sourceforge bug reports. 2. The bug tracker of Launchpad is superior, you can even send Emails to this tracker. 3. For "normal" users the usage of the Launchpad bug tracker is more complicated. For any reason Launchpad does not provide a Feature Request tracker, so the Sourceforge tracker will still be used.