Battery life is the best you can get, I keep the battery mode on "Efficiency" profile and I get 6+ hours screen on, with little or none performance worsening.
Sound still has that horrible hissing, a problem that emerged on G2 as of KitKat and was told solved in LP. Anyway since I flashed CM I had this problem, I even opened a bug report on jira and somewhere else but it was almost ignored. They told me they couldn't ear the audio bug.
Anyway, I almost removed the problem by replacing the mixer_paths.xml file in system/etc with a patched one and setting the permissions to rw-r--r--.
Link to the file:
https://xdaforums.com/attachment.php?attachmentid=3507608&d=1444933431