The v10 (Composr) alpha code on github has just been updated with a round of fixes.
Thank you to KingBast, Jason Verhagen and gemini for the bug reports.
The code is not in any official state of testing and may break randomly for uncertain periods of time without any recourse, but when people wish to test, it is useful to have had these bug reports stream in prior to the official testing to come later.
Although still unfinished, the v10 code does seem to be running pretty well nowadays. Most things are working smoothly. Don't take that as a signal to use it on any live site though because I can guarantee that the database structure will still go through some changes without any intermediate upgraders being written.
Latest v10 bug fixes pushed