What are pros and cons to CC with 1 in the Chamber?
One in the chamber:
Pros:
You will survive a real-life emergency event.
You might save another life.
Cons

only if you are a careless idiot)
You might accidentally discharge your weapon when you do not want to.
Chamber clear:
Pros:
You will get you watch the scenery while you are attacked.
Cons:
Proper end up dead or end up the victim of another crime.
I caught a fellow LEO that refused to chamber a round when on-duty and it took me shaming him, in public, before he would change his ways. It was an extreme danger and one that might have ended up costing him his life. It is beyond dumb to not chamber a round whether at home or out in the public.
You should always treat a weapon as if it has a round chambered. If you do this, then you should never run into accidental discharges. You always keep a firearm pointed away from people(except when you are defending against attacks from said person), you never place your finger in the trigger guard...well, you just need to look up and study firearm safety, if you do not already know this stuff.
Whether a person chambers a round or not is their choice, but I suggest that those who choose not to chamber a round not carry a firearm. In the end, it will end up being your firearm that is taken from you and either used against you and/or used against another person.
EDIT
Just to add:
I carry a Glock 23 with three 13 round magazines and one in the chamber. I have carried this Glock for 6+ years without any accidential discharges. I have carried a firearm since I was 19(when I entered into law enforcement) and I have always chambered a round without accidental discharges or other unintended incidents.