Hi Guille,
I'm noticing some lock ups, primarily after resolution changes, or long periods of not in interacting. I wonder whether there are a class of window events that the loop does not handle and if this produces a lock up, or rather a failure to notice that new events are incoming. I *think* I have a reproducible case on a MacBookPro whose display resolution is set to "More Space" (see the Displays setting tab).
Have a VM running on the laptop screen while the laptop is connected to an Apple Cinema display (in this configuration the laptop's retina display reverts to its default resolution).
Then disconnect the cinema display, at which point the MBP's retina display's resolution changes back to :"More Space" and, at least when I tried this morning, the VM locked up.