I've been using blue on Ubuntu for a couple of months now (Windows laptop died, a good excuse to switch). I'm using Quantal Quetzal (12.10).
It's generally working really well. I *really* like the new editor! It's a great improvement.
An issue: I've had a number of times when I change the settings of solo/mute buttons in the timeline layers and they won't "take": i.e., no change to the CSD output generated either to screen or disk. When that happens, I have to close and reopen the project, then it's fine for a while. I don't have a particular set of actions that provokes it. It's happened in more than one project.
And a feature request: I would love to be have a version of the PianoRoll that generates a line of Python code instead of a line of orchestra code (using the same templating you already have). The Python code would then be rendered just like a PythonObject. My process these days almost invariably involves writing a series of Python functions in one PythonObject that are called by other PythonObjects to generate orchestra code. It would be fantastic to be able to call those functions from with a PianoRoll.
As always, thanks for all of your work and dedication.