I've been using Nightly Builds on my 5d2 and 600D (T3i) for several months now, with mostly no problems.
Starting with the NB with the label Sep 29, 2013, my 600D won't boot. With the camera turned off, there is a red light pattern of 3 slow and 3 fast. That continues with the camera turned on. magiclantern-v2.3.NEXT.2013Sep29.600D102.zip
I have to remove the battery to get it to stop. Even when I put the battery back in (with camera off), the 3 slow + 3 fast lights continues, and the camera won't boot.
Sep 28, 2013 works find. Oct 1, 2013 won't boot either. I didn't try Sep 30.
Anyone else having this problem?