I have written about our sponsorship process loads of times already. When new contributors have no upload rights to Ubuntu yet, this process ensures that we get the code reviewed and included in Ubuntu. In the cases you branch a source package, make changes, push to Launchpad and propose a merge. The other alternative is to add a patch to a bug report and subscribe the sponsors team.
Over the last few releases we improved documentation, tools and processes and got more people involved.
I’d like to have your comment as a contributor or as a reviewer: how well does it work for you? What are you remaining gripes? What do you love about it?