Hi Tommy -
I've got 0.5.4.1 installed, and when I post something using MarsEdit, the post isn't announced to Twitter, Facebook and LinkedIn. When I post directly via WordPress or update the post and check the Update Twitter/FB/LI options and then republishing, then the post is properly announced.
Otherwise, I really love this tool and given the demise of Ping.FM for all intents and purposes, I'm looking for a long term solution and XML-RPC is a key part of my workflow. Sign me up for a donation if we can get this working!
And thanks for devoting your time to this project. I really appreciate you making these tools available to everyone.