I must say that I while I would love to see Six Apart continue to work also on the v4.x series, I really believe that open melody is an excellent product meant to continue the v4.x development, this time not by Six Apart, but from people from the movable type community.
The crew involved in Open Melody did a fantastic work so far.
Today they've launched beta 3, meant to be the last beta version. Go ahead and evaluate it, then contribute to the community with your comments and/or bug reports.
You may like to know also that RC1 is scheduled to be ready next week and shortly after v1.0, that we are all looking forward for some time.
Remember that the login details are available as always on:http://www.openmelodydemo.org/v1x.html