I think I have most of the bugs stomped out of the XML-RPC API interfaces now. Most of the big ones were squished over the last few days with the help of the ecto developer. And I just committed fixes for the last of the outstanding problems with timestamps that I was aware of.
If you are tracking CVS, watch for xmlrpc.php revision 1.39. Or test against any nightly dated 2004-03-17 or later.
If you had problems with your favorite blog client before, please try again, and post your results here.