Share your experience!
I am having lots of problems in my Xperia Z3 with the update to Android 6.0 Marshmallow, there will be an update with fixes? Something that I can do in the meantime?
Sometimes it gets stucked with a black screen when blocked, closes by itself apps, impossible to turn off alarm, etc, etc.
first could you try to boot in safe mode? to see if the problems exist? if it does it means there apps that you have installed that are causing your problems.
you can try to software repair using Xperia Companion..
Android 6.0.1 update has more bug fixes so maybe you should wait for it to be available in your region