How stable is CM 12.1 nightlies, specifically for the Nexus 6?

I'm considering taking the jump from stock 5.1.1 to CM 12.1 on my Nexus 6, but I have a few concerns, having run nightlies in the past on previous devices, specifically:

1. How is battery life? Is it the same or better than stock 5.1.1 on Nexus 6?
2. How stable? Does the phone randomly reboot?
3. Annoying bugs? Just read a thread where someone was complaining of 08/01/15 nightly as not being able to control brightness. Another user complained of not being able to send MMS.

I may just way for a milestone, if one ever comes.